root / target-m68k / helper.c @ 36bb244b
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/*
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* m68k op helpers
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*
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* Copyright (c) 2006 CodeSourcery
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* Written by Paul Brook
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <stdio.h> |
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#include "config.h" |
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#include "cpu.h" |
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#include "exec-all.h" |
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void cpu_m68k_flush_flags(CPUM68KState *env, int cc_op) |
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{ |
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int flags;
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uint32_t src; |
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uint32_t dest; |
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uint32_t tmp; |
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#define HIGHBIT 0x80000000u |
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#define SET_NZ(x) do { \ |
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if ((x) == 0) \ |
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flags |= CCF_Z; \ |
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else if ((int32_t)(x) < 0) \ |
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flags |= CCF_N; \ |
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} while (0) |
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#define SET_FLAGS_SUB(type, utype) do { \ |
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SET_NZ((type)dest); \ |
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tmp = dest + src; \ |
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if ((utype) tmp < (utype) src) \
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flags |= CCF_C; \ |
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if ((1u << (sizeof(type) * 8 - 1)) & (tmp ^ dest) & (tmp ^ src)) \ |
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flags |= CCF_V; \ |
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} while (0) |
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flags = 0;
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src = env->cc_src; |
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dest = env->cc_dest; |
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switch (cc_op) {
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case CC_OP_FLAGS:
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flags = dest; |
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break;
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case CC_OP_LOGIC:
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SET_NZ(dest); |
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break;
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case CC_OP_ADD:
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SET_NZ(dest); |
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if (dest < src)
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flags |= CCF_C; |
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tmp = dest - src; |
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if (HIGHBIT & (src ^ dest) & ~(tmp ^ src))
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flags |= CCF_V; |
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break;
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case CC_OP_SUB:
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SET_FLAGS_SUB(int32_t, uint32_t); |
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break;
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case CC_OP_CMPB:
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SET_FLAGS_SUB(int8_t, uint8_t); |
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break;
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case CC_OP_CMPW:
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SET_FLAGS_SUB(int16_t, uint16_t); |
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break;
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case CC_OP_ADDX:
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SET_NZ(dest); |
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if (dest <= src)
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flags |= CCF_C; |
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tmp = dest - src - 1;
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if (HIGHBIT & (src ^ dest) & ~(tmp ^ src))
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flags |= CCF_V; |
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break;
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case CC_OP_SUBX:
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SET_NZ(dest); |
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tmp = dest + src + 1;
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if (tmp <= src)
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flags |= CCF_C; |
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if (HIGHBIT & (tmp ^ dest) & (tmp ^ src))
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flags |= CCF_V; |
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break;
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case CC_OP_SHL:
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if (src >= 32) { |
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SET_NZ(0);
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} else {
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tmp = dest << src; |
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SET_NZ(tmp); |
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} |
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if (src && src <= 32 && (dest & (1 << (32 - src)))) |
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flags |= CCF_C; |
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break;
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case CC_OP_SHR:
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if (src >= 32) { |
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SET_NZ(0);
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} else {
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tmp = dest >> src; |
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SET_NZ(tmp); |
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} |
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if (src && src <= 32 && ((dest >> (src - 1)) & 1)) |
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flags |= CCF_C; |
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break;
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case CC_OP_SAR:
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if (src >= 32) { |
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SET_NZ(-1);
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} else {
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tmp = (int32_t)dest >> src; |
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SET_NZ(tmp); |
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} |
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if (src && src <= 32 && (((int32_t)dest >> (src - 1)) & 1)) |
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flags |= CCF_C; |
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break;
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default:
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cpu_abort(env, "Bad CC_OP %d", cc_op);
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} |
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env->cc_op = CC_OP_FLAGS; |
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env->cc_dest = flags; |
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} |
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float64 helper_sub_cmpf64(CPUM68KState *env, float64 src0, float64 src1) |
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{ |
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/* ??? This may incorrectly raise exceptions. */
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/* ??? Should flush denormals to zero. */
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float64 res; |
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res = float64_sub(src0, src1, &env->fp_status); |
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if (float64_is_nan(res)) {
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/* +/-inf compares equal against itself, but sub returns nan. */
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if (!float64_is_nan(src0)
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&& !float64_is_nan(src1)) { |
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res = 0;
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if (float64_lt_quiet(src0, res, &env->fp_status))
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res = float64_chs(res); |
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} |
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} |
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return res;
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} |