e6e5906b6e
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@2196 c046a42c-6fe2-441c-8c8c-71466251a162
150 lines
4.0 KiB
C
150 lines
4.0 KiB
C
/*
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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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}
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