Archipelago » qemu

/*

 * QEMU Cirrus VGA Emulator.

 * 

 * Copyright (c) 2004 Fabrice Bellard

 * Copyright (c) 2004 Suzu

 * 

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#include "vl.h"

#include "vga_int.h"

/***************************************

 *

 *  definitions

 *

 ***************************************/

#define qemu_MIN(a,b) ((a) < (b) ? (a) : (b))

// ID

#define CIRRUS_ID_CLGD5422  (0x23<<2)

#define CIRRUS_ID_CLGD5426  (0x24<<2)

#define CIRRUS_ID_CLGD5424  (0x25<<2)

#define CIRRUS_ID_CLGD5428  (0x26<<2)

#define CIRRUS_ID_CLGD5430  (0x28<<2)

#define CIRRUS_ID_CLGD5434  (0x2A<<2)

#define CIRRUS_ID_CLGD5446  (0x2E<<2)

// sequencer 0x07

#define CIRRUS_SR7_BPP_VGA            0x00

#define CIRRUS_SR7_BPP_SVGA           0x01

#define CIRRUS_SR7_BPP_MASK           0x0e

#define CIRRUS_SR7_BPP_8              0x00

#define CIRRUS_SR7_BPP_16_DOUBLEVCLK  0x02

#define CIRRUS_SR7_BPP_24             0x04

#define CIRRUS_SR7_BPP_16             0x06

#define CIRRUS_SR7_BPP_32             0x08

#define CIRRUS_SR7_ISAADDR_MASK       0xe0

// sequencer 0x0f

#define CIRRUS_MEMSIZE_512k        0x08

#define CIRRUS_MEMSIZE_1M          0x10

#define CIRRUS_MEMSIZE_2M          0x18

#define CIRRUS_MEMFLAGS_BANKSWITCH 0x80        // bank switching is enabled.

// sequencer 0x12

#define CIRRUS_CURSOR_SHOW         0x01

#define CIRRUS_CURSOR_HIDDENPEL    0x02

#define CIRRUS_CURSOR_LARGE        0x04        // 64x64 if set, 32x32 if clear

// sequencer 0x17

#define CIRRUS_BUSTYPE_VLBFAST   0x10

#define CIRRUS_BUSTYPE_PCI       0x20

#define CIRRUS_BUSTYPE_VLBSLOW   0x30

#define CIRRUS_BUSTYPE_ISA       0x38

#define CIRRUS_MMIO_ENABLE       0x04

#define CIRRUS_MMIO_USE_PCIADDR  0x40        // 0xb8000 if cleared.

#define CIRRUS_MEMSIZEEXT_DOUBLE 0x80

// control 0x0b

#define CIRRUS_BANKING_DUAL             0x01

#define CIRRUS_BANKING_GRANULARITY_16K  0x20        // set:16k, clear:4k

// control 0x30

#define CIRRUS_BLTMODE_BACKWARDS        0x01

#define CIRRUS_BLTMODE_MEMSYSDEST       0x02

#define CIRRUS_BLTMODE_MEMSYSSRC        0x04

#define CIRRUS_BLTMODE_TRANSPARENTCOMP  0x08

#define CIRRUS_BLTMODE_PATTERNCOPY      0x40

#define CIRRUS_BLTMODE_COLOREXPAND      0x80

#define CIRRUS_BLTMODE_PIXELWIDTHMASK   0x30

#define CIRRUS_BLTMODE_PIXELWIDTH8      0x00

#define CIRRUS_BLTMODE_PIXELWIDTH16     0x10

#define CIRRUS_BLTMODE_PIXELWIDTH24     0x20

#define CIRRUS_BLTMODE_PIXELWIDTH32     0x30

// control 0x31

#define CIRRUS_BLT_BUSY                 0x01

#define CIRRUS_BLT_START                0x02

#define CIRRUS_BLT_RESET                0x04

#define CIRRUS_BLT_FIFOUSED             0x10

// control 0x32

#define CIRRUS_ROP_0                    0x00

#define CIRRUS_ROP_SRC_AND_DST          0x05

#define CIRRUS_ROP_NOP                  0x06

#define CIRRUS_ROP_SRC_AND_NOTDST       0x09

#define CIRRUS_ROP_NOTDST               0x0b

#define CIRRUS_ROP_SRC                  0x0d

#define CIRRUS_ROP_1                    0x0e

#define CIRRUS_ROP_NOTSRC_AND_DST       0x50

#define CIRRUS_ROP_SRC_XOR_DST          0x59

#define CIRRUS_ROP_SRC_OR_DST           0x6d

#define CIRRUS_ROP_NOTSRC_OR_NOTDST     0x90

#define CIRRUS_ROP_SRC_NOTXOR_DST       0x95

#define CIRRUS_ROP_SRC_OR_NOTDST        0xad

#define CIRRUS_ROP_NOTSRC               0xd0

#define CIRRUS_ROP_NOTSRC_OR_DST        0xd6

#define CIRRUS_ROP_NOTSRC_AND_NOTDST    0xda

// memory-mapped IO

#define CIRRUS_MMIO_BLTBGCOLOR        0x00        // dword

#define CIRRUS_MMIO_BLTFGCOLOR        0x04        // dword

#define CIRRUS_MMIO_BLTWIDTH          0x08        // word

#define CIRRUS_MMIO_BLTHEIGHT         0x0a        // word

#define CIRRUS_MMIO_BLTDESTPITCH      0x0c        // word

#define CIRRUS_MMIO_BLTSRCPITCH       0x0e        // word

#define CIRRUS_MMIO_BLTDESTADDR       0x10        // dword

#define CIRRUS_MMIO_BLTSRCADDR        0x14        // dword

#define CIRRUS_MMIO_BLTWRITEMASK      0x17        // byte

#define CIRRUS_MMIO_BLTMODE           0x18        // byte

#define CIRRUS_MMIO_BLTROP            0x1a        // byte

#define CIRRUS_MMIO_BLTMODEEXT        0x1b        // byte

#define CIRRUS_MMIO_BLTTRANSPARENTCOLOR 0x1c        // word?

#define CIRRUS_MMIO_BLTTRANSPARENTCOLORMASK 0x20        // word?

#define CIRRUS_MMIO_LINEARDRAW_START_X 0x24        // word

#define CIRRUS_MMIO_LINEARDRAW_START_Y 0x26        // word

#define CIRRUS_MMIO_LINEARDRAW_END_X  0x28        // word

#define CIRRUS_MMIO_LINEARDRAW_END_Y  0x2a        // word

#define CIRRUS_MMIO_LINEARDRAW_LINESTYLE_INC 0x2c        // byte

#define CIRRUS_MMIO_LINEARDRAW_LINESTYLE_ROLLOVER 0x2d        // byte

#define CIRRUS_MMIO_LINEARDRAW_LINESTYLE_MASK 0x2e        // byte

#define CIRRUS_MMIO_LINEARDRAW_LINESTYLE_ACCUM 0x2f        // byte

#define CIRRUS_MMIO_BRESENHAM_K1      0x30        // word

#define CIRRUS_MMIO_BRESENHAM_K3      0x32        // word

#define CIRRUS_MMIO_BRESENHAM_ERROR   0x34        // word

#define CIRRUS_MMIO_BRESENHAM_DELTA_MAJOR 0x36        // word

#define CIRRUS_MMIO_BRESENHAM_DIRECTION 0x38        // byte

#define CIRRUS_MMIO_LINEDRAW_MODE     0x39        // byte

#define CIRRUS_MMIO_BLTSTATUS         0x40        // byte

// PCI 0x00: vendor, 0x02: device

#define PCI_VENDOR_CIRRUS             0x1013

#define PCI_DEVICE_CLGD5430           0x00a0        // CLGD5430 or CLGD5440

#define PCI_DEVICE_CLGD5434           0x00a8

#define PCI_DEVICE_CLGD5436           0x00ac

#define PCI_DEVICE_CLGD5446           0x00b8

#define PCI_DEVICE_CLGD5462           0x00d0

#define PCI_DEVICE_CLGD5465           0x00d6

// PCI 0x04: command(word), 0x06(word): status

#define PCI_COMMAND_IOACCESS                0x0001

#define PCI_COMMAND_MEMACCESS               0x0002

#define PCI_COMMAND_BUSMASTER               0x0004

#define PCI_COMMAND_SPECIALCYCLE            0x0008

#define PCI_COMMAND_MEMWRITEINVALID         0x0010

#define PCI_COMMAND_PALETTESNOOPING         0x0020

#define PCI_COMMAND_PARITYDETECTION         0x0040

#define PCI_COMMAND_ADDRESSDATASTEPPING     0x0080

#define PCI_COMMAND_SERR                    0x0100

#define PCI_COMMAND_BACKTOBACKTRANS         0x0200

// PCI 0x08, 0xff000000 (0x09-0x0b:class,0x08:rev)

#define PCI_CLASS_BASE_DISPLAY        0x03

// PCI 0x08, 0x00ff0000

#define PCI_CLASS_SUB_VGA             0x00

// PCI 0x0c, 0x00ff0000 (0x0c:cacheline,0x0d:latency,0x0e:headertype,0x0f:Built-in self test)

#define PCI_CLASS_HEADERTYPE_00h  0x00

// 0x10-0x3f (headertype 00h)

// PCI 0x10,0x14,0x18,0x1c,0x20,0x24: base address mapping registers

//   0x10: MEMBASE, 0x14: IOBASE(hard-coded in XFree86 3.x)

#define PCI_MAP_MEM                 0x0

#define PCI_MAP_IO                  0x1

#define PCI_MAP_MEM_ADDR_MASK       (~0xf)

#define PCI_MAP_IO_ADDR_MASK        (~0x3)

#define PCI_MAP_MEMFLAGS_32BIT      0x0

#define PCI_MAP_MEMFLAGS_32BIT_1M   0x1

#define PCI_MAP_MEMFLAGS_64BIT      0x4

#define PCI_MAP_MEMFLAGS_CACHEABLE  0x8

// PCI 0x28: cardbus CIS pointer

// PCI 0x2c: subsystem vendor id, 0x2e: subsystem id

// PCI 0x30: expansion ROM base address

#define PCI_ROMBIOS_ENABLED         0x1

// PCI 0x34: 0xffffff00=reserved, 0x000000ff=capabilities pointer

// PCI 0x38: reserved

// PCI 0x3c: 0x3c=int-line, 0x3d=int-pin, 0x3e=min-gnt, 0x3f=maax-lat

#define CIRRUS_PNPMMIO_SIZE         0x800

/* I/O and memory hook */

#define CIRRUS_HOOK_NOT_HANDLED 0

#define CIRRUS_HOOK_HANDLED 1

typedef void (*cirrus_bitblt_rop_t) (uint8_t * dst, const uint8_t * src,

                                     int dstpitch, int srcpitch,

                                     int bltwidth, int bltheight);

typedef void (*cirrus_bitblt_handler_t) (void *opaque);

typedef struct CirrusVGAState {

    /* XXX: we use the anonymous struct/union gcc 3.x extension */

    struct VGAState;

    int cirrus_linear_io_addr;

    int cirrus_mmio_io_addr;

    uint32_t cirrus_addr_mask;

    uint8_t cirrus_shadow_gr0;

    uint8_t cirrus_shadow_gr1;

    uint8_t cirrus_hidden_dac_lockindex;

    uint8_t cirrus_hidden_dac_data;

    uint32_t cirrus_bank_base[2];

    uint32_t cirrus_bank_limit[2];

    uint8_t cirrus_hidden_palette[48];

    uint32_t cirrus_hw_cursor_x;

    uint32_t cirrus_hw_cursor_y;

    int cirrus_blt_pixelwidth;

    int cirrus_blt_width;

    int cirrus_blt_height;

    int cirrus_blt_dstpitch;

    int cirrus_blt_srcpitch;

    uint32_t cirrus_blt_dstaddr;

    uint32_t cirrus_blt_srcaddr;

    uint8_t cirrus_blt_mode;

    cirrus_bitblt_rop_t cirrus_rop;

#define CIRRUS_BLTBUFSIZE 256

    uint8_t cirrus_bltbuf[CIRRUS_BLTBUFSIZE];

    uint8_t *cirrus_srcptr;

    uint8_t *cirrus_srcptr_end;

    uint32_t cirrus_srccounter;

    uint8_t *cirrus_dstptr;

    uint8_t *cirrus_dstptr_end;

    uint32_t cirrus_dstcounter;

    cirrus_bitblt_handler_t cirrus_blt_handler;

    int cirrus_blt_horz_counter;

} CirrusVGAState;

typedef struct PCICirrusVGAState {

    PCIDevice dev;

    CirrusVGAState cirrus_vga;

} PCICirrusVGAState;

/***************************************

 *

 *  prototypes.

 *

 ***************************************/

static void cirrus_bitblt_reset(CirrusVGAState * s);

/***************************************

 *

 *  raster operations

 *

 ***************************************/

#define IMPLEMENT_FORWARD_BITBLT(name,opline) \

  static void \

  cirrus_bitblt_rop_fwd_##name( \

    uint8_t *dst,const uint8_t *src, \

    int dstpitch,int srcpitch, \

    int bltwidth,int bltheight) \

  { \

    int x,y; \

    dstpitch -= bltwidth; \

    srcpitch -= bltwidth; \

    for (y = 0; y < bltheight; y++) { \

      for (x = 0; x < bltwidth; x++) { \

        opline; \

        dst++; \

        src++; \

        } \

      dst += dstpitch; \

      src += srcpitch; \

      } \

    }

#define IMPLEMENT_BACKWARD_BITBLT(name,opline) \

  static void \

  cirrus_bitblt_rop_bkwd_##name( \

    uint8_t *dst,const uint8_t *src, \

    int dstpitch,int srcpitch, \

    int bltwidth,int bltheight) \

  { \

    int x,y; \

    dstpitch += bltwidth; \

    srcpitch += bltwidth; \

    for (y = 0; y < bltheight; y++) { \

      for (x = 0; x < bltwidth; x++) { \

        opline; \

        dst--; \

        src--; \

      } \

      dst += dstpitch; \

      src += srcpitch; \

    } \

  }

IMPLEMENT_FORWARD_BITBLT(0, *dst = 0)

    IMPLEMENT_FORWARD_BITBLT(src_and_dst, *dst = (*src) & (*dst))

    IMPLEMENT_FORWARD_BITBLT(nop, (void) 0)

    IMPLEMENT_FORWARD_BITBLT(src_and_notdst, *dst = (*src) & (~(*dst)))

    IMPLEMENT_FORWARD_BITBLT(notdst, *dst = ~(*dst))

    IMPLEMENT_FORWARD_BITBLT(src, *dst = *src)

    IMPLEMENT_FORWARD_BITBLT(1, *dst = 0xff)

    IMPLEMENT_FORWARD_BITBLT(notsrc_and_dst, *dst = (~(*src)) & (*dst))

    IMPLEMENT_FORWARD_BITBLT(src_xor_dst, *dst = (*src) ^ (*dst))

    IMPLEMENT_FORWARD_BITBLT(src_or_dst, *dst = (*src) | (*dst))

    IMPLEMENT_FORWARD_BITBLT(notsrc_or_notdst, *dst = (~(*src)) | (~(*dst)))

    IMPLEMENT_FORWARD_BITBLT(src_notxor_dst, *dst = ~((*src) ^ (*dst)))

    IMPLEMENT_FORWARD_BITBLT(src_or_notdst, *dst = (*src) | (~(*dst)))

    IMPLEMENT_FORWARD_BITBLT(notsrc, *dst = (~(*src)))

    IMPLEMENT_FORWARD_BITBLT(notsrc_or_dst, *dst = (~(*src)) | (*dst))

    IMPLEMENT_FORWARD_BITBLT(notsrc_and_notdst, *dst = (~(*src)) & (~(*dst)))

    IMPLEMENT_BACKWARD_BITBLT(0, *dst = 0)

    IMPLEMENT_BACKWARD_BITBLT(src_and_dst, *dst = (*src) & (*dst))

    IMPLEMENT_BACKWARD_BITBLT(nop, (void) 0)

    IMPLEMENT_BACKWARD_BITBLT(src_and_notdst, *dst = (*src) & (~(*dst)))

    IMPLEMENT_BACKWARD_BITBLT(notdst, *dst = ~(*dst))

    IMPLEMENT_BACKWARD_BITBLT(src, *dst = *src)

    IMPLEMENT_BACKWARD_BITBLT(1, *dst = 0xff)

    IMPLEMENT_BACKWARD_BITBLT(notsrc_and_dst, *dst = (~(*src)) & (*dst))

    IMPLEMENT_BACKWARD_BITBLT(src_xor_dst, *dst = (*src) ^ (*dst))

    IMPLEMENT_BACKWARD_BITBLT(src_or_dst, *dst = (*src) | (*dst))

    IMPLEMENT_BACKWARD_BITBLT(notsrc_or_notdst, *dst = (~(*src)) | (~(*dst)))

    IMPLEMENT_BACKWARD_BITBLT(src_notxor_dst, *dst = ~((*src) ^ (*dst)))

    IMPLEMENT_BACKWARD_BITBLT(src_or_notdst, *dst = (*src) | (~(*dst)))

    IMPLEMENT_BACKWARD_BITBLT(notsrc, *dst = (~(*src)))

    IMPLEMENT_BACKWARD_BITBLT(notsrc_or_dst, *dst = (~(*src)) | (*dst))

    IMPLEMENT_BACKWARD_BITBLT(notsrc_and_notdst, *dst = (~(*src)) & (~(*dst)))

static cirrus_bitblt_rop_t cirrus_get_fwd_rop_handler(uint8_t rop)

{

    cirrus_bitblt_rop_t rop_handler = cirrus_bitblt_rop_fwd_nop;

    switch (rop) {

    case CIRRUS_ROP_0:

        rop_handler = cirrus_bitblt_rop_fwd_0;

        break;

    case CIRRUS_ROP_SRC_AND_DST:

        rop_handler = cirrus_bitblt_rop_fwd_src_and_dst;

        break;

    case CIRRUS_ROP_NOP:

        rop_handler = cirrus_bitblt_rop_fwd_nop;

        break;

    case CIRRUS_ROP_SRC_AND_NOTDST:

        rop_handler = cirrus_bitblt_rop_fwd_src_and_notdst;

        break;

    case CIRRUS_ROP_NOTDST:

        rop_handler = cirrus_bitblt_rop_fwd_notdst;

        break;

    case CIRRUS_ROP_SRC:

        rop_handler = cirrus_bitblt_rop_fwd_src;

        break;

    case CIRRUS_ROP_1:

        rop_handler = cirrus_bitblt_rop_fwd_1;

        break;

    case CIRRUS_ROP_NOTSRC_AND_DST:

        rop_handler = cirrus_bitblt_rop_fwd_notsrc_and_dst;

        break;

    case CIRRUS_ROP_SRC_XOR_DST:

        rop_handler = cirrus_bitblt_rop_fwd_src_xor_dst;

        break;

    case CIRRUS_ROP_SRC_OR_DST:

        rop_handler = cirrus_bitblt_rop_fwd_src_or_dst;

        break;

    case CIRRUS_ROP_NOTSRC_OR_NOTDST:

        rop_handler = cirrus_bitblt_rop_fwd_notsrc_or_notdst;

        break;

    case CIRRUS_ROP_SRC_NOTXOR_DST:

        rop_handler = cirrus_bitblt_rop_fwd_src_notxor_dst;

        break;

    case CIRRUS_ROP_SRC_OR_NOTDST:

        rop_handler = cirrus_bitblt_rop_fwd_src_or_notdst;

        break;

    case CIRRUS_ROP_NOTSRC:

        rop_handler = cirrus_bitblt_rop_fwd_notsrc;

        break;

    case CIRRUS_ROP_NOTSRC_OR_DST:

        rop_handler = cirrus_bitblt_rop_fwd_notsrc_or_dst;

        break;

    case CIRRUS_ROP_NOTSRC_AND_NOTDST:

        rop_handler = cirrus_bitblt_rop_fwd_notsrc_and_notdst;

        break;

    default:

#ifdef DEBUG_CIRRUS

        printf("unknown ROP %02x\n", rop);

#endif

        break;

    }

    return rop_handler;

}

static cirrus_bitblt_rop_t cirrus_get_bkwd_rop_handler(uint8_t rop)

{

    cirrus_bitblt_rop_t rop_handler = cirrus_bitblt_rop_bkwd_nop;

    switch (rop) {

    case CIRRUS_ROP_0:

        rop_handler = cirrus_bitblt_rop_bkwd_0;

        break;

    case CIRRUS_ROP_SRC_AND_DST:

        rop_handler = cirrus_bitblt_rop_bkwd_src_and_dst;

        break;

    case CIRRUS_ROP_NOP:

        rop_handler = cirrus_bitblt_rop_bkwd_nop;

        break;

    case CIRRUS_ROP_SRC_AND_NOTDST:

        rop_handler = cirrus_bitblt_rop_bkwd_src_and_notdst;

        break;

    case CIRRUS_ROP_NOTDST:

        rop_handler = cirrus_bitblt_rop_bkwd_notdst;

        break;

    case CIRRUS_ROP_SRC:

        rop_handler = cirrus_bitblt_rop_bkwd_src;

        break;

    case CIRRUS_ROP_1:

        rop_handler = cirrus_bitblt_rop_bkwd_1;

        break;

    case CIRRUS_ROP_NOTSRC_AND_DST:

        rop_handler = cirrus_bitblt_rop_bkwd_notsrc_and_dst;

        break;

    case CIRRUS_ROP_SRC_XOR_DST:

        rop_handler = cirrus_bitblt_rop_bkwd_src_xor_dst;

        break;

    case CIRRUS_ROP_SRC_OR_DST:

        rop_handler = cirrus_bitblt_rop_bkwd_src_or_dst;

        break;

    case CIRRUS_ROP_NOTSRC_OR_NOTDST:

        rop_handler = cirrus_bitblt_rop_bkwd_notsrc_or_notdst;

        break;

    case CIRRUS_ROP_SRC_NOTXOR_DST:

        rop_handler = cirrus_bitblt_rop_bkwd_src_notxor_dst;

        break;

    case CIRRUS_ROP_SRC_OR_NOTDST:

        rop_handler = cirrus_bitblt_rop_bkwd_src_or_notdst;

        break;

    case CIRRUS_ROP_NOTSRC:

        rop_handler = cirrus_bitblt_rop_bkwd_notsrc;

        break;

    case CIRRUS_ROP_NOTSRC_OR_DST:

        rop_handler = cirrus_bitblt_rop_bkwd_notsrc_or_dst;

        break;

    case CIRRUS_ROP_NOTSRC_AND_NOTDST:

        rop_handler = cirrus_bitblt_rop_bkwd_notsrc_and_notdst;

        break;

    default:

#ifdef DEBUG_CIRRUS

        printf("unknown ROP %02x\n", rop);

#endif

        break;

    }

    return rop_handler;

}

/***************************************

 *

 *  color expansion

 *

 ***************************************/

static void

cirrus_colorexpand_8(CirrusVGAState * s, uint8_t * dst,

                     const uint8_t * src, int count)

{

    int x;

    uint8_t colors[2];

    unsigned bits;

    unsigned bitmask;

    int srcskipleft = 0;

    colors[0] = s->gr[0x00];

    colors[1] = s->gr[0x01];

    bitmask = 0x80 >> srcskipleft;

    bits = *src++;

    for (x = 0; x < count; x++) {

        if ((bitmask & 0xff) == 0) {

            bitmask = 0x80;

            bits = *src++;

        }

        *dst++ = colors[!!(bits & bitmask)];

        bitmask >>= 1;

    }

}

static void

cirrus_colorexpand_16(CirrusVGAState * s, uint8_t * dst,

                      const uint8_t * src, int count)

{

    int x;

    uint8_t colors[2][2];

    unsigned bits;

    unsigned bitmask;

    unsigned index;

    int srcskipleft = 0;

    colors[0][0] = s->gr[0x00];

    colors[0][1] = s->gr[0x10];

    colors[1][0] = s->gr[0x01];

    colors[1][1] = s->gr[0x11];

    bitmask = 0x80 >> srcskipleft;

    bits = *src++;

    for (x = 0; x < count; x++) {

        if ((bitmask & 0xff) == 0) {

            bitmask = 0x80;

            bits = *src++;

        }

        index = !!(bits & bitmask);

        *dst++ = colors[index][0];

        *dst++ = colors[index][1];

        bitmask >>= 1;

    }

}

static void

cirrus_colorexpand_24(CirrusVGAState * s, uint8_t * dst,

                      const uint8_t * src, int count)

{

    int x;

    uint8_t colors[2][3];

    unsigned bits;

    unsigned bitmask;

    unsigned index;

    int srcskipleft = 0;

    colors[0][0] = s->gr[0x00];

    colors[0][1] = s->gr[0x10];

    colors[0][2] = s->gr[0x12];

    colors[1][0] = s->gr[0x01];

    colors[1][1] = s->gr[0x11];

    colors[1][2] = s->gr[0x13];

    bitmask = 0x80 << srcskipleft;

    bits = *src++;

    for (x = 0; x < count; x++) {

        if ((bitmask & 0xff) == 0) {

            bitmask = 0x80;

            bits = *src++;

        }

        index = !!(bits & bitmask);

        *dst++ = colors[index][0];

        *dst++ = colors[index][1];

        *dst++ = colors[index][2];

        bitmask >>= 1;

    }

}

static void

cirrus_colorexpand_32(CirrusVGAState * s, uint8_t * dst,

                      const uint8_t * src, int count)

{

    int x;

    uint8_t colors[2][4];

    unsigned bits;

    unsigned bitmask;

    unsigned index;

    int srcskipleft = 0;

    colors[0][0] = s->gr[0x00];

    colors[0][1] = s->gr[0x10];

    colors[0][2] = s->gr[0x12];

    colors[0][3] = s->gr[0x14];

    colors[1][0] = s->gr[0x01];

    colors[1][1] = s->gr[0x11];

    colors[1][2] = s->gr[0x13];

    colors[1][3] = s->gr[0x15];

    bitmask = 0x80 << srcskipleft;

    bits = *src++;

    for (x = 0; x < count; x++) {

        if ((bitmask & 0xff) == 0) {

            bitmask = 0x80;

            bits = *src++;

        }

        index = !!(bits & bitmask);

        *dst++ = colors[index][0];

        *dst++ = colors[index][1];

        *dst++ = colors[index][2];

        *dst++ = colors[index][3];

        bitmask >>= 1;

    }

}

static void

cirrus_colorexpand(CirrusVGAState * s, uint8_t * dst, const uint8_t * src,

                   int count)

{

    switch (s->cirrus_blt_pixelwidth) {

    case 1:

        cirrus_colorexpand_8(s, dst, src, count);

        break;

    case 2:

        cirrus_colorexpand_16(s, dst, src, count);

        break;

    case 3:

        cirrus_colorexpand_24(s, dst, src, count);

        break;

    case 4:

        cirrus_colorexpand_32(s, dst, src, count);

        break;

    default:

#ifdef DEBUG_CIRRUS

        printf("cirrus: COLOREXPAND pixelwidth %d - unimplemented\n",

               s->cirrus_blt_pixelwidth);

#endif

        break;

    }

}

static void cirrus_invalidate_region(CirrusVGAState * s, int off_begin,

                                     int off_pitch, int bytesperline,

                                     int lines)

{

    int y;

    int off_cur;

    int off_cur_end;

    for (y = 0; y < lines; y++) {

        off_cur = off_begin;

        off_cur_end = off_cur + bytesperline;

        off_cur &= TARGET_PAGE_MASK;

        while (off_cur < off_cur_end) {

            cpu_physical_memory_set_dirty(s->vram_offset + off_cur);

            off_cur += TARGET_PAGE_SIZE;

        }

        off_begin += off_pitch;

    }

}

static int cirrus_bitblt_common_patterncopy(CirrusVGAState * s,

                                            const uint8_t * src)

{

    uint8_t work_colorexp[256];

    uint8_t *dst;

    uint8_t *dstc;

    int x, y;

    int tilewidth, tileheight;

    int patternbytes = s->cirrus_blt_pixelwidth * 8;

    if (s->cirrus_blt_mode & CIRRUS_BLTMODE_COLOREXPAND) {

        cirrus_colorexpand(s, work_colorexp, src, 8 * 8);

        src = work_colorexp;

        s->cirrus_blt_mode &= ~CIRRUS_BLTMODE_COLOREXPAND;

    }

    if (s->cirrus_blt_mode & ~CIRRUS_BLTMODE_PATTERNCOPY) {

#ifdef DEBUG_CIRRUS

        printf("cirrus: blt mode %02x (pattercopy) - unimplemented\n",

               s->cirrus_blt_mode);

#endif

        return 0;

    }

    dst = s->vram_ptr + s->cirrus_blt_dstaddr;

    for (y = 0; y < s->cirrus_blt_height; y += 8) {

        dstc = dst;

        tileheight = qemu_MIN(8, s->cirrus_blt_height - y);

        for (x = 0; x < s->cirrus_blt_width; x += patternbytes) {

            tilewidth = qemu_MIN(patternbytes, s->cirrus_blt_width - x);

            (*s->cirrus_rop) (dstc, src,

                              s->cirrus_blt_dstpitch, patternbytes,

                              tilewidth, tileheight);

            dstc += patternbytes;

        }

        dst += s->cirrus_blt_dstpitch * 8;

    }

    cirrus_invalidate_region(s, s->cirrus_blt_dstaddr,

                             s->cirrus_blt_dstpitch, s->cirrus_blt_width,

                             s->cirrus_blt_height);

    return 1;

}

/***************************************

 *

 *  bitblt (video-to-video)

 *

 ***************************************/

static int cirrus_bitblt_videotovideo_patterncopy(CirrusVGAState * s)

{

    return cirrus_bitblt_common_patterncopy(s,

                                            s->vram_ptr +

                                            s->cirrus_blt_srcaddr);

}

static int cirrus_bitblt_videotovideo_copy(CirrusVGAState * s)

{

    if ((s->cirrus_blt_mode & CIRRUS_BLTMODE_COLOREXPAND) != 0) {

#ifdef DEBUG_CIRRUS

        printf("cirrus: CIRRUS_BLTMODE_COLOREXPAND - unimplemented\n");

#endif

        return 0;

    }

    if ((s->cirrus_blt_mode & (~CIRRUS_BLTMODE_BACKWARDS)) != 0) {

#ifdef DEBUG_CIRRUS

        printf("cirrus: blt mode %02x - unimplemented\n",

               s->cirrus_blt_mode);

#endif

        return 0;

    }

    (*s->cirrus_rop) (s->vram_ptr + s->cirrus_blt_dstaddr,

                      s->vram_ptr + s->cirrus_blt_srcaddr,

                      s->cirrus_blt_dstpitch, s->cirrus_blt_srcpitch,

                      s->cirrus_blt_width, s->cirrus_blt_height);

    cirrus_invalidate_region(s, s->cirrus_blt_dstaddr,

                             s->cirrus_blt_dstpitch, s->cirrus_blt_width,

                             s->cirrus_blt_height);

    return 1;

}

/***************************************

 *

 *  bitblt (cpu-to-video)

 *

 ***************************************/

static void cirrus_bitblt_cputovideo_patterncopy(void *opaque)

{

    CirrusVGAState *s = (CirrusVGAState *) opaque;

    int data_count;

    data_count = s->cirrus_srcptr - &s->cirrus_bltbuf[0];

    if (data_count > 0) {

        if (data_count != s->cirrus_srccounter) {

#ifdef DEBUG_CIRRUS

            printf("cirrus: internal error\n");

#endif

        } else {

            cirrus_bitblt_common_patterncopy(s, &s->cirrus_bltbuf[0]);

        }

        cirrus_bitblt_reset(s);

    }

}

static void cirrus_bitblt_cputovideo_copy(void *opaque)

{

    CirrusVGAState *s = (CirrusVGAState *) opaque;

    int data_count;

    int data_avail;

    uint8_t work_colorexp[256];

    uint8_t *src_ptr = NULL;

    int src_avail = 0;

    int src_processing;

    int src_linepad = 0;

    if (s->cirrus_blt_height <= 0) {

        s->cirrus_srcptr = s->cirrus_srcptr_end;

        return;

    }

    s->cirrus_srcptr = &s->cirrus_bltbuf[0];

    while (1) {

        /* get BLT source. */

        if (src_avail <= 0) {

            data_count = s->cirrus_srcptr_end - s->cirrus_srcptr;

            if (data_count <= 0)

                break;

            if (s->cirrus_blt_mode & CIRRUS_BLTMODE_COLOREXPAND) {

                if (s->cirrus_blt_mode & ~CIRRUS_BLTMODE_COLOREXPAND) {

#ifdef DEBUG_CIRRUS

                    printf("cirrus: unsupported\n");

#endif

                    cirrus_bitblt_reset(s);

                    return;

                }

                data_avail = qemu_MIN(data_count, 256 / 32);

                cirrus_colorexpand(s, work_colorexp, s->cirrus_srcptr,

                                   data_avail * 8);

                src_ptr = &work_colorexp[0];

                src_avail = data_avail * 8 * s->cirrus_blt_pixelwidth;

                s->cirrus_srcptr += data_avail;

                src_linepad =

                    ((s->cirrus_blt_width + 7) / 8) * 8 -

                    s->cirrus_blt_width;

                src_linepad *= s->cirrus_blt_pixelwidth;

            } else {

                if (s->cirrus_blt_mode != 0) {

#ifdef DEBUG_CIRRUS

                    printf("cirrus: unsupported\n");

#endif

                    cirrus_bitblt_reset(s);

                    return;

                }

                src_ptr = s->cirrus_srcptr;

                src_avail =

                    data_count / s->cirrus_blt_pixelwidth *

                    s->cirrus_blt_pixelwidth;

                s->cirrus_srcptr += src_avail;

            }

            if (src_avail <= 0)

                break;

        }

        /* 1-line BLT */

        src_processing =

            s->cirrus_blt_srcpitch - s->cirrus_blt_horz_counter;

        src_processing = qemu_MIN(src_avail, src_processing);

        (*s->cirrus_rop) (s->vram_ptr + s->cirrus_blt_dstaddr,

                          src_ptr, 0, 0, src_processing, 1);

        cirrus_invalidate_region(s, s->cirrus_blt_dstaddr, 0,

                                 src_processing, 1);

        s->cirrus_blt_dstaddr += src_processing;

        src_ptr += src_processing;

        src_avail -= src_processing;

        s->cirrus_blt_horz_counter += src_processing;

        if (s->cirrus_blt_horz_counter >= s->cirrus_blt_srcpitch) {

            src_ptr += src_linepad;

            src_avail -= src_linepad;

            s->cirrus_blt_dstaddr +=

                s->cirrus_blt_dstpitch - s->cirrus_blt_srcpitch;

            s->cirrus_blt_horz_counter = 0;

            s->cirrus_blt_height--;

            if (s->cirrus_blt_height <= 0) {

                s->cirrus_srcptr = s->cirrus_srcptr_end;

                return;

            }

        }

    }

}

static void cirrus_bitblt_cputovideo_next(CirrusVGAState * s)

{

    int copy_count;

    int avail_count;

    s->cirrus_blt_handler(s);

    if (s->cirrus_srccounter > 0) {

        s->cirrus_srccounter -= s->cirrus_srcptr - &s->cirrus_bltbuf[0];

        copy_count = s->cirrus_srcptr_end - s->cirrus_srcptr;

        memmove(&s->cirrus_bltbuf[0], s->cirrus_srcptr, copy_count);

        avail_count = qemu_MIN(CIRRUS_BLTBUFSIZE, s->cirrus_srccounter);

        s->cirrus_srcptr = &s->cirrus_bltbuf[0];

        s->cirrus_srcptr_end = s->cirrus_srcptr + avail_count;

        if (s->cirrus_srccounter <= 0) {

            cirrus_bitblt_reset(s);

        }

    }

}

/***************************************

 *

 *  bitblt wrapper

 *

 ***************************************/

static void cirrus_bitblt_reset(CirrusVGAState * s)

{

    s->gr[0x31] &=

        ~(CIRRUS_BLT_START | CIRRUS_BLT_BUSY | CIRRUS_BLT_FIFOUSED);

    s->cirrus_srcptr = &s->cirrus_bltbuf[0];

    s->cirrus_srcptr_end = &s->cirrus_bltbuf[0];

    s->cirrus_srccounter = 0;

    s->cirrus_dstptr = &s->cirrus_bltbuf[0];

    s->cirrus_dstptr_end = &s->cirrus_bltbuf[0];

    s->cirrus_dstcounter = 0;

    s->cirrus_blt_handler = NULL;

}

static int cirrus_bitblt_cputovideo(CirrusVGAState * s)

{

    s->cirrus_blt_mode &= ~CIRRUS_BLTMODE_MEMSYSSRC;

    s->cirrus_srcptr = &s->cirrus_bltbuf[0];

    s->cirrus_srcptr_end = &s->cirrus_bltbuf[0];

    if (s->cirrus_blt_mode & CIRRUS_BLTMODE_PATTERNCOPY) {

        if (s->cirrus_blt_mode & CIRRUS_BLTMODE_COLOREXPAND) {

            s->cirrus_srccounter = 8;

        } else {

            s->cirrus_srccounter = 8 * 8 * s->cirrus_blt_pixelwidth;

        }

        s->cirrus_blt_srcpitch = 0;

        s->cirrus_blt_handler = cirrus_bitblt_cputovideo_patterncopy;

    } else {

        if (s->cirrus_blt_mode & CIRRUS_BLTMODE_COLOREXPAND) {

            s->cirrus_srccounter =

                ((s->cirrus_blt_width + 7) / 8) * s->cirrus_blt_height;

            s->cirrus_blt_srcpitch =

                s->cirrus_blt_width * s->cirrus_blt_pixelwidth;

        } else {

            s->cirrus_srccounter =

                s->cirrus_blt_width * s->cirrus_blt_height;

            s->cirrus_blt_srcpitch = s->cirrus_blt_width;

        }

        /* 4-byte alignment */

        s->cirrus_srccounter = (s->cirrus_srccounter + 3) & (~3);

        s->cirrus_blt_handler = cirrus_bitblt_cputovideo_copy;

        s->cirrus_blt_horz_counter = 0;

    }

    cirrus_bitblt_cputovideo_next(s);

    return 1;

}

static int cirrus_bitblt_videotocpu(CirrusVGAState * s)

{

    /* XXX */

#ifdef DEBUG_CIRRUS

    printf("cirrus: bitblt (video to cpu) is not implemented yet\n");

#endif

    return 0;

}

static int cirrus_bitblt_videotovideo(CirrusVGAState * s)

{

    int ret;

    if (s->cirrus_blt_mode & CIRRUS_BLTMODE_PATTERNCOPY) {

        ret = cirrus_bitblt_videotovideo_patterncopy(s);

    } else {

        ret = cirrus_bitblt_videotovideo_copy(s);

    }

    if (ret)

        cirrus_bitblt_reset(s);

    return ret;

}

static void cirrus_bitblt_start(CirrusVGAState * s)

{

    uint8_t blt_rop;

    s->cirrus_blt_width = (s->gr[0x20] | (s->gr[0x21] << 8)) + 1;

    s->cirrus_blt_height = (s->gr[0x22] | (s->gr[0x23] << 8)) + 1;

    s->cirrus_blt_dstpitch = (s->gr[0x24] | (s->gr[0x25] << 8));

    s->cirrus_blt_srcpitch = (s->gr[0x26] | (s->gr[0x27] << 8));

    s->cirrus_blt_dstaddr =

        (s->gr[0x28] | (s->gr[0x29] << 8) | (s->gr[0x2a] << 16));

    s->cirrus_blt_srcaddr =

        (s->gr[0x2c] | (s->gr[0x2d] << 8) | (s->gr[0x2e] << 16));

    s->cirrus_blt_mode = s->gr[0x30];

    blt_rop = s->gr[0x32];

    switch (s->cirrus_blt_mode & CIRRUS_BLTMODE_PIXELWIDTHMASK) {

    case CIRRUS_BLTMODE_PIXELWIDTH8:

        s->cirrus_blt_pixelwidth = 1;

        break;

    case CIRRUS_BLTMODE_PIXELWIDTH16:

        s->cirrus_blt_pixelwidth = 2;

        break;

    case CIRRUS_BLTMODE_PIXELWIDTH24:

        s->cirrus_blt_pixelwidth = 3;

        break;

    case CIRRUS_BLTMODE_PIXELWIDTH32:

        s->cirrus_blt_pixelwidth = 4;

        break;

    default:

#ifdef DEBUG_CIRRUS

        printf("cirrus: bitblt - pixel width is unknown\n");

#endif

        goto bitblt_ignore;

    }

    s->cirrus_blt_mode &= ~CIRRUS_BLTMODE_PIXELWIDTHMASK;

    if ((s->

         cirrus_blt_mode & (CIRRUS_BLTMODE_MEMSYSSRC |

                            CIRRUS_BLTMODE_MEMSYSDEST))

        == (CIRRUS_BLTMODE_MEMSYSSRC | CIRRUS_BLTMODE_MEMSYSDEST)) {

#ifdef DEBUG_CIRRUS

        printf("cirrus: bitblt - memory-to-memory copy is requested\n");

#endif

        goto bitblt_ignore;

    }

    if (s->cirrus_blt_mode & CIRRUS_BLTMODE_BACKWARDS) {

        s->cirrus_blt_dstpitch = -s->cirrus_blt_dstpitch;

        s->cirrus_blt_srcpitch = -s->cirrus_blt_srcpitch;

        s->cirrus_rop = cirrus_get_bkwd_rop_handler(blt_rop);

    } else {

        s->cirrus_rop = cirrus_get_fwd_rop_handler(blt_rop);

    }

    // setup bitblt engine.

    if (s->cirrus_blt_mode & CIRRUS_BLTMODE_MEMSYSSRC) {

        if (!cirrus_bitblt_cputovideo(s))

            goto bitblt_ignore;

    } else if (s->cirrus_blt_mode & CIRRUS_BLTMODE_MEMSYSDEST) {

        if (!cirrus_bitblt_videotocpu(s))

            goto bitblt_ignore;

    } else {

        if (!cirrus_bitblt_videotovideo(s))

            goto bitblt_ignore;

    }

    return;

  bitblt_ignore:;

    cirrus_bitblt_reset(s);

}

static void cirrus_write_bitblt(CirrusVGAState * s, unsigned reg_value)

{

    unsigned old_value;

    old_value = s->gr[0x31];

    s->gr[0x31] = reg_value;

    if (((old_value & CIRRUS_BLT_RESET) != 0) &&

        ((reg_value & CIRRUS_BLT_RESET) == 0)) {

        cirrus_bitblt_reset(s);

    } else if (((old_value & CIRRUS_BLT_START) == 0) &&

               ((reg_value & CIRRUS_BLT_START) != 0)) {

        s->gr[0x31] |= CIRRUS_BLT_BUSY;

        cirrus_bitblt_start(s);

    }

}

/***************************************

 *

 *  basic parameters

 *

 ***************************************/

static void cirrus_get_offsets(VGAState *s1, 

                                   uint32_t *pline_offset,

                                   uint32_t *pstart_addr)

{

    CirrusVGAState * s = (CirrusVGAState *)s1;

    uint32_t start_addr;

    uint32_t line_offset;

    line_offset = s->cr[0x13]

        | ((s->cr[0x1b] & 0x10) << 8);

    line_offset <<= 3;

    *pline_offset = line_offset;

    start_addr = (s->cr[0x0c] << 8)

        | s->cr[0x0d]

        | ((s->cr[0x1b] & 0x01) << 16)

        | ((s->cr[0x1b] & 0x0c) << 15)

        | ((s->cr[0x1d] & 0x80) << 12);

    *pstart_addr = start_addr;

}

static uint32_t cirrus_get_bpp16_depth(CirrusVGAState * s)

{

    uint32_t ret = 16;

    switch (s->cirrus_hidden_dac_data & 0xf) {

    case 0:

        ret = 15;

        break;                        /* Sierra HiColor */

    case 1:

        ret = 16;

        break;                        /* XGA HiColor */

    default:

#ifdef DEBUG_CIRRUS

        printf("cirrus: invalid DAC value %x in 16bpp\n",

               (s->cirrus_hidden_dac_data & 0xf));

#endif

        ret = 15;                /* XXX */

        break;

    }

    return ret;

}

static int cirrus_get_bpp(VGAState *s1)

{

    CirrusVGAState * s = (CirrusVGAState *)s1;

    uint32_t ret = 8;

    if ((s->sr[0x07] & 0x01) != 0) {

        /* Cirrus SVGA */

        switch (s->sr[0x07] & CIRRUS_SR7_BPP_MASK) {

        case CIRRUS_SR7_BPP_8:

            ret = 8;

            break;

        case CIRRUS_SR7_BPP_16_DOUBLEVCLK:

            ret = cirrus_get_bpp16_depth(s);

            break;

        case CIRRUS_SR7_BPP_24:

            ret = 24;

            break;

        case CIRRUS_SR7_BPP_16:

            ret = cirrus_get_bpp16_depth(s);

            break;

        case CIRRUS_SR7_BPP_32:

            ret = 32;

            break;

        default:

#ifdef DEBUG_CIRRUS

            printf("cirrus: unknown bpp - sr7=%x\n", s->sr[0x7]);

#endif

            ret = 8;

            break;

        }

    } else {

        /* VGA */

        ret = 8;

    }

    return ret;

}

/***************************************

 *

 * bank memory

 *

 ***************************************/

static void cirrus_update_bank_ptr(CirrusVGAState * s, unsigned bank_index)

{

    unsigned offset;

    unsigned limit;

    if ((s->gr[0x0b] & 0x01) != 0)        /* dual bank */

        offset = s->gr[0x09 + bank_index];

    else                        /* single bank */

        offset = s->gr[0x09];

    if ((s->gr[0x0b] & 0x20) != 0)

        offset <<= 14;

    else

        offset <<= 12;

    if (s->vram_size <= offset)

        limit = 0;

    else

        limit = s->vram_size - offset;

    if (((s->gr[0x0b] & 0x01) == 0) && (bank_index != 0)) {

        if (limit > 0x8000) {

            offset += 0x8000;

            limit -= 0x8000;

        } else {

            limit = 0;

        }

    }

    if (limit > 0) {

        s->cirrus_bank_base[bank_index] = offset;

        s->cirrus_bank_limit[bank_index] = limit;

    } else {

        s->cirrus_bank_base[bank_index] = 0;

        s->cirrus_bank_limit[bank_index] = 0;

    }

}

/***************************************

 *

 *  I/O access between 0x3c4-0x3c5

 *

 ***************************************/

static int

cirrus_hook_read_sr(CirrusVGAState * s, unsigned reg_index, int *reg_value)

{

    switch (reg_index) {

    case 0x00:                        // Standard VGA

    case 0x01:                        // Standard VGA

    case 0x02:                        // Standard VGA

    case 0x03:                        // Standard VGA

    case 0x04:                        // Standard VGA

        return CIRRUS_HOOK_NOT_HANDLED;

    case 0x06:                        // Unlock Cirrus extensions

        *reg_value = s->sr[reg_index];

        break;

    case 0x05:                        // ???

    case 0x07:                        // Extended Sequencer Mode

    case 0x08:                        // EEPROM Control

    case 0x09:                        // Scratch Register 0

    case 0x0a:                        // Scratch Register 1

    case 0x0b:                        // VCLK 0

    case 0x0c:                        // VCLK 1

    case 0x0d:                        // VCLK 2

    case 0x0e:                        // VCLK 3

    case 0x0f:                        // DRAM Control

    case 0x10:

    case 0x30:

    case 0x50:

    case 0x70:                        // Graphics Cursor X

    case 0x90:

    case 0xb0:

    case 0xd0:

    case 0xf0:                        // Graphics Cursor X

    case 0x11:

    case 0x31:

    case 0x51:

    case 0x71:                        // Graphics Cursor Y

    case 0x91:

    case 0xb1:

    case 0xd1:

    case 0xf1:                        // Graphics Cursor Y

    case 0x12:                        // Graphics Cursor Attribute

    case 0x13:                        // Graphics Cursor Pattern Address

    case 0x14:                        // Scratch Register 2

    case 0x15:                        // Scratch Register 3

    case 0x16:                        // Performance Tuning Register

    case 0x17:                        // Configuration Readback and Extended Control

    case 0x18:                        // Signature Generator Control

    case 0x19:                        // Signal Generator Result

    case 0x1a:                        // Signal Generator Result

    case 0x1b:                        // VCLK 0 Denominator & Post

    case 0x1c:                        // VCLK 1 Denominator & Post

    case 0x1d:                        // VCLK 2 Denominator & Post

    case 0x1e:                        // VCLK 3 Denominator & Post

    case 0x1f:                        // BIOS Write Enable and MCLK select

#ifdef DEBUG_CIRRUS

        printf("cirrus: handled inport sr_index %02x\n", reg_index);

#endif

        *reg_value = s->sr[reg_index];

        break;

    default:

#ifdef DEBUG_CIRRUS

        printf("cirrus: inport sr_index %02x\n", reg_index);

#endif

        *reg_value = 0xff;

        break;

    }

    return CIRRUS_HOOK_HANDLED;

}

static int

cirrus_hook_write_sr(CirrusVGAState * s, unsigned reg_index, int reg_value)

{

    switch (reg_index) {

    case 0x00:                        // Standard VGA

    case 0x01:                        // Standard VGA

    case 0x02:                        // Standard VGA

    case 0x03:                        // Standard VGA

    case 0x04:                        // Standard VGA

        return CIRRUS_HOOK_NOT_HANDLED;

    case 0x06:                        // Unlock Cirrus extensions

        reg_value &= 0x17;

        if (reg_value == 0x12) {

            s->sr[reg_index] = 0x12;

        } else {

            s->sr[reg_index] = 0x0f;

        }

        break;

    case 0x10:

    case 0x30:

    case 0x50:

    case 0x70:                        // Graphics Cursor X

    case 0x90:

    case 0xb0:

    case 0xd0:

    case 0xf0:                        // Graphics Cursor X

        s->sr[0x10] = reg_value;

        s->cirrus_hw_cursor_x = ((reg_index << 3) & 0x700) | reg_value;

        break;

    case 0x11:

    case 0x31:

    case 0x51:

    case 0x71:                        // Graphics Cursor Y

    case 0x91:

    case 0xb1:

    case 0xd1:

    case 0xf1:                        // Graphics Cursor Y

        s->sr[0x11] = reg_value;

        s->cirrus_hw_cursor_y = ((reg_index << 3) & 0x700) | reg_value;

        break;

    case 0x07:                        // Extended Sequencer Mode

    case 0x08:                        // EEPROM Control

    case 0x09:                        // Scratch Register 0

    case 0x0a:                        // Scratch Register 1

    case 0x0b:                        // VCLK 0

    case 0x0c:                        // VCLK 1

    case 0x0d:                        // VCLK 2

    case 0x0e:                        // VCLK 3

    case 0x0f:                        // DRAM Control

    case 0x12:                        // Graphics Cursor Attribute

    case 0x13:                        // Graphics Cursor Pattern Address

    case 0x14:                        // Scratch Register 2

    case 0x15:                        // Scratch Register 3

    case 0x16:                        // Performance Tuning Register

    case 0x17:                        // Configuration Readback and Extended Control

    case 0x18:                        // Signature Generator Control

    case 0x19:                        // Signature Generator Result

    case 0x1a:                        // Signature Generator Result

    case 0x1b:                        // VCLK 0 Denominator & Post

    case 0x1c:                        // VCLK 1 Denominator & Post

    case 0x1d:                        // VCLK 2 Denominator & Post

    case 0x1e:                        // VCLK 3 Denominator & Post

    case 0x1f:                        // BIOS Write Enable and MCLK select

        s->sr[reg_index] = reg_value;

#ifdef DEBUG_CIRRUS

        printf("cirrus: handled outport sr_index %02x, sr_value %02x\n",