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NEC Vx0: Swap the two operands in CMPSB/CMPSW, fixes #6764.

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Also do some refactoring to make thinking back to old 808x instructions easier for debugging purposes.
This commit is contained in:
OBattler
2026-01-30 04:03:20 +01:00
parent 484a61f65a
commit d1d3941542
3 changed files with 1701 additions and 1738 deletions
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3287
src/cpu/808x.c
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File diff suppressed because it is too large Load Diff

133
src/cpu/vx0.c
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@@ -224,20 +224,6 @@ const uint8_t opf_0f[256] = { 0, 0, 0, 0, 0, 0,
int nx = 0;
static uint32_t cpu_src = 0;
static uint32_t cpu_dest = 0;
static uint32_t cpu_data = 0;
static int oldc;
static int cpu_alu_op;
static int completed = 1;
static int in_rep = 0;
static int repeating = 0;
static int rep_c_flag = 0;
static int clear_lock = 0;
static int noint = 0;
static int tempc_fpu = 0;
static int started = 0;
static int group_delay = 0;
static int modrm_loaded = 0;
@@ -246,8 +232,6 @@ static int in_hlt = 0;
static int retem = 0;
static int halted = 0;
static uint32_t * ovr_seg = NULL;
/* Pointer tables needed for segment overrides. */
static uint32_t * opseg[4];
@@ -489,6 +473,8 @@ void i8080_port_out(UNUSED(void* priv), uint8_t port, uint8_t val)
void
reset_vx0(int hard)
{
reset_808x(hard);
halted = 0;
in_hlt = 0;
in_0f = 0;
@@ -1854,9 +1840,53 @@ do_mod_rm(void)
}
static void
decode(void)
decode_modrm(void)
{
uint8_t op_f;
modrm_loaded = 0;
if (is_nec) {
if (in_0f)
op_f = (uint8_t) opf_0f[opcode];
else
op_f = (uint8_t) opf_nec[opcode];
} else
op_f = (uint8_t) opf[opcode];
if (op_f & OP_GRP) {
do_mod_rm();
modrm_loaded = 1;
op_f |= (OP_MRM | OP_EA);
if (opcode >= 0xf0) {
op_f |= OP_DELAY;
group_delay = 1;
}
}
if (!modrm_loaded && (op_f & OP_MRM)) {
do_mod_rm();
modrm_loaded = 1;
}
if (modrm_loaded && !(op_f & OP_EA)) {
if (is_nec)
do_cycle();
else {
if (opcode == 0x8f) {
if (cpu_mod == 3)
do_cycles_i(2);
} else
do_cycles_i(2);
}
}
}
static void
decode(void)
{
uint8_t prefix = 0;
if (halted)
@@ -1864,8 +1894,6 @@ decode(void)
else
opcode = biu_pfq_fetchb_common();
modrm_loaded = 0;
while (1) {
prefix = 0;
@@ -1913,43 +1941,6 @@ decode(void)
opcode = biu_pfq_fetchb_common();
}
if (is_nec) {
if (in_0f)
op_f = (uint8_t) opf_0f[opcode];
else
op_f = (uint8_t) opf_nec[opcode];
} else
op_f = (uint8_t) opf[opcode];
if (op_f & OP_GRP) {
do_mod_rm();
modrm_loaded = 1;
op_f |= (OP_MRM | OP_EA);
if (opcode >= 0xf0) {
op_f |= OP_DELAY;
group_delay = 1;
}
}
if (!modrm_loaded && (op_f & OP_MRM)) {
do_mod_rm();
modrm_loaded = 1;
}
if (modrm_loaded && !(op_f & OP_EA)) {
if (is_nec)
do_cycle();
else {
if (opcode == 0x8f) {
if (cpu_mod == 3)
do_cycles_i(2);
} else
do_cycles_i(2);
}
}
}
static void
@@ -1992,6 +1983,10 @@ string_op(int bits)
lods_di(bits);
tmpa = cpu_data;
lods(bits);
/* Swap them or else the operation goes wrong. */
uint32_t tmpa2 = tmpa;
tmpa = cpu_data;
cpu_data = tmpa2;
} else {
lods(bits);
tmpa = cpu_data;
@@ -4735,7 +4730,16 @@ execvx0(int cycs)
startx86();
}
#ifdef DEBUG_INSTRUCTIONS
if (repeating) {
if ((opcode >= 0xa0) && (opcode <= 0xaf) && (opcode != 0x8e)) {
execx86_instruction();
goto check_completed;
}
} else {
#else
if (!repeating) {
#endif
cpu_state.oldpc = cpu_state.pc;
if (clear_lock) {
@@ -4743,9 +4747,21 @@ execvx0(int cycs)
clear_lock = 0;
}
if (!is_nec || (cpu_state.flags & MD_FLAG))
if (!is_nec || (cpu_state.flags & MD_FLAG)) {
decode();
#ifdef DEBUG_INSTRUCTIONS
if ((opcode >= 0xa0) && (opcode <= 0xaf) && (opcode != 0x8e)) {
oldc = cpu_state.flags & C_FLAG;
execx86_instruction();
goto check_completed;
}
#endif
decode_modrm();
}
oldc = cpu_state.flags & C_FLAG;
}
@@ -4753,6 +4769,9 @@ execvx0(int cycs)
execute_instruction();
#ifdef DEBUG_INSTRUCTIONS
check_completed:
#endif
if (completed) {
if (opcode != 0xf4)
finalize();

19
src/cpu/vx0_biu.h
View File

@@ -76,7 +76,8 @@ enum {
DMA_STATE_OPERATING
};
/* Temporary BIU externs - move to 808x_biu.h. */
extern void execx86_instruction(void);
extern void biu_resume_on_queue_read(void);
extern void wait_vx0(int c);
extern void biu_reset(void);
@@ -106,6 +107,15 @@ extern void biu_wait_for_read_finish(void);
extern uint8_t biu_preload_byte;
extern int nx;
extern int oldc;
extern int cpu_alu_op;
extern int completed;
extern int in_rep;
extern int repeating;
extern int rep_c_flag;
extern int noint;
extern int tempc_fpu;
extern int clear_lock;
extern int schedule_fetch;
extern int in_lock;
@@ -113,4 +123,11 @@ extern int bus_request_type;
extern int pic_data;
extern int biu_queue_preload;
extern uint32_t cpu_src;
extern uint32_t cpu_dest;
extern uint32_t cpu_data;
extern uint32_t *ovr_seg;
#endif /*EMU_808X_BIU_H*/