Archipelago » qemu

/*

 *  ARM helper routines

 *

 *  Copyright (c) 2005-2007 CodeSourcery, LLC

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, see <http://www.gnu.org/licenses/>.

 */

#include "exec.h"

#include "helpers.h"

#define SIGNBIT (uint32_t)0x80000000

#define SIGNBIT64 ((uint64_t)1 << 63)

void raise_exception(int tt)

{

    env->exception_index = tt;

    cpu_loop_exit();

}

uint32_t HELPER(neon_tbl)(uint32_t ireg, uint32_t def,

                          uint32_t rn, uint32_t maxindex)

{

    uint32_t val;

    uint32_t tmp;

    int index;

    int shift;

    uint64_t *table;

    table = (uint64_t *)&env->vfp.regs[rn];

    val = 0;

    for (shift = 0; shift < 32; shift += 8) {

        index = (ireg >> shift) & 0xff;

        if (index < maxindex) {

            tmp = (table[index >> 3] >> ((index & 7) << 3)) & 0xff;

            val |= tmp << shift;

        } else {

            val |= def & (0xff << shift);

        }

    }

    return val;

}

#if !defined(CONFIG_USER_ONLY)

#define MMUSUFFIX _mmu

#define SHIFT 0

#include "softmmu_template.h"

#define SHIFT 1

#include "softmmu_template.h"

#define SHIFT 2

#include "softmmu_template.h"

#define SHIFT 3

#include "softmmu_template.h"

/* try to fill the TLB and return an exception if error. If retaddr is

   NULL, it means that the function was called in C code (i.e. not

   from generated code or from helper.c) */

/* XXX: fix it to restore all registers */

void tlb_fill (target_ulong addr, int is_write, int mmu_idx, void *retaddr)

{

    TranslationBlock *tb;

    CPUState *saved_env;

    unsigned long pc;

    int ret;

    /* XXX: hack to restore env in all cases, even if not called from

       generated code */

    saved_env = env;

    env = cpu_single_env;

    ret = cpu_arm_handle_mmu_fault(env, addr, is_write, mmu_idx, 1);

    if (unlikely(ret)) {

        if (retaddr) {

            /* now we have a real cpu fault */

            pc = (unsigned long)retaddr;

            tb = tb_find_pc(pc);

            if (tb) {

                /* the PC is inside the translated code. It means that we have

                   a virtual CPU fault */

                cpu_restore_state(tb, env, pc, NULL);

            }

        }

        raise_exception(env->exception_index);

    }

    env = saved_env;

}

#endif

/* FIXME: Pass an axplicit pointer to QF to CPUState, and move saturating

   instructions into helper.c  */

uint32_t HELPER(add_setq)(uint32_t a, uint32_t b)

{

    uint32_t res = a + b;

    if (((res ^ a) & SIGNBIT) && !((a ^ b) & SIGNBIT))

        env->QF = 1;

    return res;

}

uint32_t HELPER(add_saturate)(uint32_t a, uint32_t b)

{

    uint32_t res = a + b;

    if (((res ^ a) & SIGNBIT) && !((a ^ b) & SIGNBIT)) {

        env->QF = 1;

        res = ~(((int32_t)a >> 31) ^ SIGNBIT);

    }

    return res;

}

uint32_t HELPER(sub_saturate)(uint32_t a, uint32_t b)

{

    uint32_t res = a - b;

    if (((res ^ a) & SIGNBIT) && ((a ^ b) & SIGNBIT)) {

        env->QF = 1;

        res = ~(((int32_t)a >> 31) ^ SIGNBIT);

    }

    return res;

}

uint32_t HELPER(double_saturate)(int32_t val)

{

    uint32_t res;

    if (val >= 0x40000000) {

        res = ~SIGNBIT;

        env->QF = 1;

    } else if (val <= (int32_t)0xc0000000) {

        res = SIGNBIT;

        env->QF = 1;

    } else {

        res = val << 1;

    }

    return res;

}

uint32_t HELPER(add_usaturate)(uint32_t a, uint32_t b)

{

    uint32_t res = a + b;

    if (res < a) {

        env->QF = 1;

        res = ~0;

    }

    return res;

}

uint32_t HELPER(sub_usaturate)(uint32_t a, uint32_t b)

{

    uint32_t res = a - b;

    if (res > a) {

        env->QF = 1;

        res = 0;

    }

    return res;

}

/* Signed saturation.  */

static inline uint32_t do_ssat(int32_t val, int shift)

{

    int32_t top;

    uint32_t mask;

    top = val >> shift;

    mask = (1u << shift) - 1;

    if (top > 0) {

        env->QF = 1;

        return mask;

    } else if (top < -1) {

        env->QF = 1;

        return ~mask;

    }

    return val;

}

/* Unsigned saturation.  */

static inline uint32_t do_usat(int32_t val, int shift)

{

    uint32_t max;

    max = (1u << shift) - 1;

    if (val < 0) {

        env->QF = 1;

        return 0;

    } else if (val > max) {

        env->QF = 1;

        return max;

    }

    return val;

}

/* Signed saturate.  */

uint32_t HELPER(ssat)(uint32_t x, uint32_t shift)

{

    return do_ssat(x, shift);

}

/* Dual halfword signed saturate.  */

uint32_t HELPER(ssat16)(uint32_t x, uint32_t shift)

{

    uint32_t res;

    res = (uint16_t)do_ssat((int16_t)x, shift);

    res |= do_ssat(((int32_t)x) >> 16, shift) << 16;

    return res;

}

/* Unsigned saturate.  */

uint32_t HELPER(usat)(uint32_t x, uint32_t shift)

{

    return do_usat(x, shift);

}

/* Dual halfword unsigned saturate.  */

uint32_t HELPER(usat16)(uint32_t x, uint32_t shift)

{

    uint32_t res;

    res = (uint16_t)do_usat((int16_t)x, shift);

    res |= do_usat(((int32_t)x) >> 16, shift) << 16;

    return res;

}

void HELPER(wfi)(void)

{

    env->exception_index = EXCP_HLT;

    env->halted = 1;

    cpu_loop_exit();

}

void HELPER(exception)(uint32_t excp)

{

    env->exception_index = excp;

    cpu_loop_exit();

}

uint32_t HELPER(cpsr_read)(void)

{

    return cpsr_read(env) & ~CPSR_EXEC;

}

void HELPER(cpsr_write)(uint32_t val, uint32_t mask)

{

    cpsr_write(env, val, mask);

}

/* Access to user mode registers from privileged modes.  */

uint32_t HELPER(get_user_reg)(uint32_t regno)

{

    uint32_t val;

    if (regno == 13) {

        val = env->banked_r13[0];

    } else if (regno == 14) {

        val = env->banked_r14[0];

    } else if (regno >= 8

               && (env->uncached_cpsr & 0x1f) == ARM_CPU_MODE_FIQ) {

        val = env->usr_regs[regno - 8];

    } else {

        val = env->regs[regno];

    }

    return val;

}

void HELPER(set_user_reg)(uint32_t regno, uint32_t val)

{

    if (regno == 13) {

        env->banked_r13[0] = val;

    } else if (regno == 14) {

        env->banked_r14[0] = val;

    } else if (regno >= 8

               && (env->uncached_cpsr & 0x1f) == ARM_CPU_MODE_FIQ) {

        env->usr_regs[regno - 8] = val;

    } else {

        env->regs[regno] = val;

    }

}

/* ??? Flag setting arithmetic is awkward because we need to do comparisons.

   The only way to do that in TCG is a conditional branch, which clobbers

   all our temporaries.  For now implement these as helper functions.  */

uint32_t HELPER (add_cc)(uint32_t a, uint32_t b)

{

    uint32_t result;

    result = a + b;

    env->NF = env->ZF = result;

    env->CF = result < a;

    env->VF = (a ^ b ^ -1) & (a ^ result);

    return result;

}

uint32_t HELPER(adc_cc)(uint32_t a, uint32_t b)

{

    uint32_t result;

    if (!env->CF) {

        result = a + b;

        env->CF = result < a;

    } else {

        result = a + b + 1;

        env->CF = result <= a;

    }

    env->VF = (a ^ b ^ -1) & (a ^ result);

    env->NF = env->ZF = result;

    return result;

}

uint32_t HELPER(sub_cc)(uint32_t a, uint32_t b)

{

    uint32_t result;

    result = a - b;

    env->NF = env->ZF = result;

    env->CF = a >= b;

    env->VF = (a ^ b) & (a ^ result);

    return result;

}

uint32_t HELPER(sbc_cc)(uint32_t a, uint32_t b)

{

    uint32_t result;

    if (!env->CF) {

        result = a - b - 1;

        env->CF = a > b;

    } else {

        result = a - b;

        env->CF = a >= b;

    }

    env->VF = (a ^ b) & (a ^ result);

    env->NF = env->ZF = result;

    return result;

}

/* Similarly for variable shift instructions.  */

uint32_t HELPER(shl)(uint32_t x, uint32_t i)

{

    int shift = i & 0xff;

    if (shift >= 32)

        return 0;

    return x << shift;

}

uint32_t HELPER(shr)(uint32_t x, uint32_t i)

{

    int shift = i & 0xff;

    if (shift >= 32)

        return 0;

    return (uint32_t)x >> shift;

}

uint32_t HELPER(sar)(uint32_t x, uint32_t i)

{

    int shift = i & 0xff;

    if (shift >= 32)

        shift = 31;

    return (int32_t)x >> shift;

}

uint32_t HELPER(shl_cc)(uint32_t x, uint32_t i)

{

    int shift = i & 0xff;

    if (shift >= 32) {

        if (shift == 32)

            env->CF = x & 1;

        else

            env->CF = 0;

        return 0;

    } else if (shift != 0) {

        env->CF = (x >> (32 - shift)) & 1;

        return x << shift;

    }

    return x;

}

uint32_t HELPER(shr_cc)(uint32_t x, uint32_t i)

{

    int shift = i & 0xff;

    if (shift >= 32) {

        if (shift == 32)

            env->CF = (x >> 31) & 1;

        else

            env->CF = 0;

        return 0;

    } else if (shift != 0) {

        env->CF = (x >> (shift - 1)) & 1;

        return x >> shift;

    }

    return x;

}

uint32_t HELPER(sar_cc)(uint32_t x, uint32_t i)

{

    int shift = i & 0xff;

    if (shift >= 32) {

        env->CF = (x >> 31) & 1;

        return (int32_t)x >> 31;

    } else if (shift != 0) {

        env->CF = (x >> (shift - 1)) & 1;

        return (int32_t)x >> shift;

    }

    return x;

}

uint32_t HELPER(ror_cc)(uint32_t x, uint32_t i)

{

    int shift1, shift;

    shift1 = i & 0xff;

    shift = shift1 & 0x1f;

    if (shift == 0) {

        if (shift1 != 0)

            env->CF = (x >> 31) & 1;

        return x;

    } else {

        env->CF = (x >> (shift - 1)) & 1;

        return ((uint32_t)x >> shift) | (x << (32 - shift));

    }

}