diff options
Diffstat (limited to 'target-m68k/helper.c')
| -rw-r--r-- | target-m68k/helper.c | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/target-m68k/helper.c b/target-m68k/helper.c new file mode 100644 index 0000000000..6b8f18d15d --- /dev/null +++ b/target-m68k/helper.c @@ -0,0 +1,149 @@ +/* + * 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; +} |