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AltairZ80: Add support for NMI interrupts.

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This commit is contained in:
Howard M. Harte 2023-01-22 13:41:04 -08:00
parent 11e555bb20
commit 023cd3b387
1 changed files with 37 additions and 14 deletions
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51
AltairZ80/altairz80_cpu.c
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@ -44,6 +44,9 @@
#define INST_MAX_BYTES 4 /* instruction max bytes */
#define IFF1 1 /* Interrupt flip-flop 1 */
#define IFF2 2 /* Interrupt flip-flop 2 */
#define FLAG_C 1
#define FLAG_N 2
#define FLAG_P 4
@ -249,6 +252,7 @@ UNIT cpu_unit = {
int32 IP_S; /* IP register (8086) */
int32 FLAGS_S; /* flags register (8086) */
int32 SR = 0; /* switch register */
uint32 nmiInterrupt = 0; /* Non-maskable Interrupt */
uint32 vectorInterrupt = 0; /* VI0-7 Vector Interrupt bitfield */
uint8 dataBus[MAX_INT_VECTORS]; /* Vector Interrupt data bus value */
static int32 bankSelect = 0; /* determines selected memory bank */
@ -494,6 +498,8 @@ REG cpu_reg[] = {
}, /* 87 */
{ DRDATAD(M68KVAR, m68kvariant, 17, "M68K Type (68000, 68010, etc.)"),
}, /* 88 */
{ HRDATAD(NMI, nmiInterrupt, 1, "NMI Interrupt pseudo register"),
}, /* 89 */
{ NULL }
};
@ -2192,7 +2198,7 @@ static t_stat sim_instr_mmu (void) {
SP = SP_S;
IX = IX_S;
IY = IY_S;
specialProcessing = clockFrequency | timerInterrupt | vectorInterrupt | keyboardInterrupt | sim_brk_summ;
specialProcessing = clockFrequency | nmiInterrupt | timerInterrupt | vectorInterrupt | keyboardInterrupt | sim_brk_summ;
tStates = 0;
if (rtc_avail) {
startTime = sim_os_msec();
@ -2214,7 +2220,7 @@ static t_stat sim_instr_mmu (void) {
} else /* make sure that sim_os_msec() is not called later */
clockFrequency = startTime = tStatesInSlice = 0;
}
specialProcessing = clockFrequency | timerInterrupt | vectorInterrupt | keyboardInterrupt | sim_brk_summ;
specialProcessing = clockFrequency | nmiInterrupt | timerInterrupt | vectorInterrupt | keyboardInterrupt | sim_brk_summ;
}
if (specialProcessing) { /* quick check for special processing */
@ -2228,11 +2234,28 @@ static t_stat sim_instr_mmu (void) {
sim_os_ms_sleep(startTime - now);
}
if (timerInterrupt && (IFF_S & 1)) {
if (nmiInterrupt) {
nmiInterrupt = FALSE;
specialProcessing = clockFrequency | sim_brk_summ;
IFF_S &= IFF2; /* Clear IFF1 */
CHECK_BREAK_TWO_BYTES_EXTENDED(SP - 2, SP - 1, (nmiInterrupt = TRUE, IFF_S |= IFF1));
if ((GetBYTE(PC) == HALTINSTRUCTION) && ((cpu_unit.flags & UNIT_CPU_STOPONHALT) == 0)) {
PUSH(PC + 1);
PCQ_ENTRY(PC);
}
else {
PUSH(PC);
PCQ_ENTRY(PC - 1);
}
tStates += 11;
PC = 0x0066;
}
if (timerInterrupt && (IFF_S & IFF1)) {
timerInterrupt = FALSE;
specialProcessing = clockFrequency | sim_brk_summ;
IFF_S = 0; /* disable interrupts */
CHECK_BREAK_TWO_BYTES_EXTENDED(SP - 2, SP - 1, (timerInterrupt = TRUE, IFF_S |= 1));
CHECK_BREAK_TWO_BYTES_EXTENDED(SP - 2, SP - 1, (timerInterrupt = TRUE, IFF_S |= (IFF1 | IFF2)));
if ((GetBYTE(PC) == HALTINSTRUCTION) && ((cpu_unit.flags & UNIT_CPU_STOPONHALT) == 0)) {
PUSH(PC + 1);
PCQ_ENTRY(PC);
@ -2243,7 +2266,7 @@ static t_stat sim_instr_mmu (void) {
PC = timerInterruptHandler & ADDRMASK;
}
if ((IM_S == 1) && vectorInterrupt && (IFF_S & 1)) { /* Z80 Interrupt Mode 1 */
if ((IM_S == 1) && vectorInterrupt && (IFF_S & IFF1)) { /* Z80 Interrupt Mode 1 */
uint32 tempVectorInterrupt = vectorInterrupt;
uint8 intVector = 0;
@ -2256,7 +2279,7 @@ static t_stat sim_instr_mmu (void) {
specialProcessing = clockFrequency | sim_brk_summ;
IFF_S = 0; /* disable interrupts */
CHECK_BREAK_TWO_BYTES_EXTENDED(SP - 2, SP - 1, (vectorInterrupt |= (1 << intVector), IFF_S |= 1));
CHECK_BREAK_TWO_BYTES_EXTENDED(SP - 2, SP - 1, (vectorInterrupt |= (1 << intVector), IFF_S |= (IFF1 | IFF2)));
if ((GetBYTE(PC) == HALTINSTRUCTION) && ((cpu_unit.flags & UNIT_CPU_STOPONHALT) == 0)) {
PUSH(PC + 1);
PCQ_ENTRY(PC);
@ -2270,7 +2293,7 @@ static t_stat sim_instr_mmu (void) {
sim_debug(INT_MSG, &cpu_dev, ADDRESS_FORMAT
" INT(mode=1 intVector=%d PC=%04X)\n", PCX, intVector, PC);
} else if ((IM_S == 2) && vectorInterrupt && (IFF_S & 1)) {
} else if ((IM_S == 2) && vectorInterrupt && (IFF_S & IFF1)) {
int32 vector;
uint32 tempVectorInterrupt = vectorInterrupt;
uint8 intVector = 0;
@ -2284,7 +2307,7 @@ static t_stat sim_instr_mmu (void) {
specialProcessing = clockFrequency | sim_brk_summ;
IFF_S = 0; /* disable interrupts */
CHECK_BREAK_TWO_BYTES_EXTENDED(SP - 2, SP - 1, (vectorInterrupt |= (1 << intVector), IFF_S |= 1));
CHECK_BREAK_TWO_BYTES_EXTENDED(SP - 2, SP - 1, (vectorInterrupt |= (1 << intVector), IFF_S |= (IFF1 | IFF2)));
if ((GetBYTE(PC) == HALTINSTRUCTION) && ((cpu_unit.flags & UNIT_CPU_STOPONHALT) == 0)) {
PUSH(PC + 1);
PCQ_ENTRY(PC);
@ -2301,11 +2324,11 @@ static t_stat sim_instr_mmu (void) {
" INT(mode=2 intVector=%d vector=%04X PC=%04X)\n", PCX, intVector, vector, PC);
}
if (keyboardInterrupt && (IFF_S & 1)) {
if (keyboardInterrupt && (IFF_S & IFF1)) {
keyboardInterrupt = FALSE;
specialProcessing = clockFrequency | sim_brk_summ;
IFF_S = 0; /* disable interrupts */
CHECK_BREAK_TWO_BYTES_EXTENDED(SP - 2, SP - 1, (keyboardInterrupt = TRUE, IFF_S |= 1));
CHECK_BREAK_TWO_BYTES_EXTENDED(SP - 2, SP - 1, (keyboardInterrupt = TRUE, IFF_S |= (IFF1 | IFF2)));
if ((GetBYTE(PC) == HALTINSTRUCTION) && ((cpu_unit.flags & UNIT_CPU_STOPONHALT) == 0)) {
PUSH(PC + 1);
PCQ_ENTRY(PC);
@ -2338,7 +2361,7 @@ static t_stat sim_instr_mmu (void) {
Instruction to execute (ex. RST0-7) is on the data bus
NOTE: does not support multi-byte instructions such as CALL
*/
if ((IM_S == 0) && vectorInterrupt && (IFF_S & 1)) { /* 8080/Z80 Interrupt Mode 0 */
if ((IM_S == 0) && vectorInterrupt && (IFF_S & IFF1)) { /* 8080/Z80 Interrupt Mode 0 */
uint32 tempVectorInterrupt = vectorInterrupt;
uint8 intVector = 0;
@ -5020,7 +5043,7 @@ static t_stat sim_instr_mmu (void) {
case 0x57: /* LD A,I */
tStates += 9;
AF = (AF & 0x29) | (IR_S & ~0xff) | ((IR_S >> 8) & 0x80) | (((IR_S & ~0xff) == 0) << 6) | ((IFF_S & 2) << 1);
AF = (AF & 0x29) | (IR_S & ~0xff) | ((IR_S >> 8) & 0x80) | (((IR_S & ~0xff) == 0) << 6) | ((IFF_S & IFF2) << 1);
break;
case 0x58: /* IN E,(C) */
@ -5061,7 +5084,7 @@ static t_stat sim_instr_mmu (void) {
case 0x5f: /* LD A,R */
tStates += 9;
AF = (AF & 0x29) | ((IR_S & 0xff) << 8) | (IR_S & 0x80) |
(((IR_S & 0xff) == 0) << 6) | ((IFF_S & 2) << 1);
(((IR_S & 0xff) == 0) << 6) | ((IFF_S & IFF2) << 1);
break;
case 0x60: /* IN H,(C) */
@ -5553,7 +5576,7 @@ static t_stat sim_instr_mmu (void) {
case 0xfb: /* EI */
tStates += 4; /* EI 4 */
IFF_S = 3;
IFF_S = (IFF1 | IFF2);
break;
case 0xfc: /* CALL M,nnnn */