helper.c
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/*
* m68k op helpers
*
* Copyright (c) 2006 CodeSourcery
* Written by Paul Brook
*
* 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
* 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, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <stdio.h>
#include "config.h"
#include "cpu.h"
#include "exec-all.h"
void cpu_m68k_flush_flags(CPUM68KState *env, int cc_op)
{
int flags;
uint32_t src;
uint32_t dest;
uint32_t tmp;
#define HIGHBIT 0x80000000u
#define SET_NZ(x) do { \
if ((x) == 0) \
flags |= CCF_Z; \
else if ((int32_t)(x) < 0) \
flags |= CCF_N; \
} while (0)
#define SET_FLAGS_SUB(type, utype) do { \
SET_NZ((type)dest); \
tmp = dest + src; \
if ((utype) tmp < (utype) src) \
flags |= CCF_C; \
if ((1u << (sizeof(type) * 8 - 1)) & (tmp ^ dest) & (tmp ^ src)) \
flags |= CCF_V; \
} while (0)
flags = 0;
src = env->cc_src;
dest = env->cc_dest;
switch (cc_op) {
case CC_OP_FLAGS:
flags = dest;
break;
case CC_OP_LOGIC:
SET_NZ(dest);
break;
case CC_OP_ADD:
SET_NZ(dest);
if (dest < src)
flags |= CCF_C;
tmp = dest - src;
if (HIGHBIT & (src ^ dest) & ~(tmp ^ src))
flags |= CCF_V;
break;
case CC_OP_SUB:
SET_FLAGS_SUB(int32_t, uint32_t);
break;
case CC_OP_CMPB:
SET_FLAGS_SUB(int8_t, uint8_t);
break;
case CC_OP_CMPW:
SET_FLAGS_SUB(int16_t, uint16_t);
break;
case CC_OP_ADDX:
SET_NZ(dest);
if (dest <= src)
flags |= CCF_C;
tmp = dest - src - 1;
if (HIGHBIT & (src ^ dest) & ~(tmp ^ src))
flags |= CCF_V;
break;
case CC_OP_SUBX:
SET_NZ(dest);
tmp = dest + src + 1;
if (tmp <= src)
flags |= CCF_C;
if (HIGHBIT & (tmp ^ dest) & (tmp ^ src))
flags |= CCF_V;
break;
case CC_OP_SHL:
if (src >= 32) {
SET_NZ(0);
} else {
tmp = dest << src;
SET_NZ(tmp);
}
if (src && src <= 32 && (dest & (1 << (32 - src))))
flags |= CCF_C;
break;
case CC_OP_SHR:
if (src >= 32) {
SET_NZ(0);
} else {
tmp = dest >> src;
SET_NZ(tmp);
}
if (src && src <= 32 && ((dest >> (src - 1)) & 1))
flags |= CCF_C;
break;
case CC_OP_SAR:
if (src >= 32) {
SET_NZ(-1);
} else {
tmp = (int32_t)dest >> src;
SET_NZ(tmp);
}
if (src && src <= 32 && (((int32_t)dest >> (src - 1)) & 1))
flags |= CCF_C;
break;
default:
cpu_abort(env, "Bad CC_OP %d", cc_op);
}
env->cc_op = CC_OP_FLAGS;
env->cc_dest = flags;
}
float64 helper_sub_cmpf64(CPUM68KState *env, float64 src0, float64 src1)
{
/* ??? This may incorrectly raise exceptions. */
/* ??? Should flush denormals to zero. */
float64 res;
res = float64_sub(src0, src1, &env->fp_status);
if (float64_is_nan(res)) {
/* +/-inf compares equal against itself, but sub returns nan. */
if (!float64_is_nan(src0)
&& !float64_is_nan(src1)) {
res = 0;
if (float64_lt_quiet(src0, res, &env->fp_status))
res = float64_chs(res);
}
}
return res;
}