fork of PCE focusing on macplus, supporting DaynaPort SCSI network emulation
8086: Allow interrupts only if IF was set before and after the instruction
This ensures that instructions like popf or sti that set the interrupt
flag are not immediately followed by an interrupt.
+15
-22
+10
-14
src/cpu/e8086/e8086.c
+10
-14
src/cpu/e8086/e8086.c
···
5
5
/*****************************************************************************
6
6
* File name: src/cpu/e8086/e8086.c *
7
7
* Created: 1996-04-28 by Hampa Hug <hampa@hampa.ch> *
8
-
* Copyright: (C) 1996-2019 Hampa Hug <hampa@hampa.ch> *
8
+
* Copyright: (C) 1996-2021 Hampa Hug <hampa@hampa.ch> *
9
9
*****************************************************************************/
10
10
11
11
/*****************************************************************************
···
392
392
e86_set_cs (c, e86_get_mem16 (c, 0, ofs + 2));
393
393
c->flg &= ~(E86_FLG_I | E86_FLG_T);
394
394
395
-
c->trap_flag = c->flg;
395
+
c->save_flags = e86_get_flags (c);
396
396
397
397
e86_pq_init (c);
398
398
}
···
465
465
e86_set_ip (c, 0xfff0);
466
466
e86_set_flags (c, c->reset_flags);
467
467
468
-
c->trap_flag = 0;
468
+
c->save_flags = 0;
469
469
470
470
c->pq_cnt = 0;
471
471
···
503
503
c->cur_ip = c->ip;
504
504
}
505
505
506
-
c->trap_flag = c->flg;
506
+
c->save_flags = e86_get_flags (c);
507
507
508
508
irq = c->irq;
509
-
510
-
c->enable_int = 1;
511
509
512
510
do {
513
511
e86_pq_fill (c);
···
531
529
532
530
c->opcnt += 1;
533
531
534
-
if (c->enable_int) {
535
-
if (c->trap_flag & E86_FLG_T) {
536
-
c->state &= ~E86_STATE_HALT;
537
-
e86_trap (c, 1);
538
-
}
539
-
else if (irq && c->irq && e86_get_if (c)) {
540
-
e86_irq_ack (c);
541
-
}
532
+
if (c->save_flags & E86_FLG_T) {
533
+
c->state &= ~E86_STATE_HALT;
534
+
e86_trap (c, 1);
535
+
}
536
+
else if (irq && c->irq && (c->save_flags & e86_get_flags (c) & E86_FLG_I)) {
537
+
e86_irq_ack (c);
542
538
}
543
539
}
544
540
+2
-3
src/cpu/e8086/e8086.h
+2
-3
src/cpu/e8086/e8086.h
···
5
5
/*****************************************************************************
6
6
* File name: src/cpu/e8086/e8086.h *
7
7
* Created: 1996-04-28 by Hampa Hug <hampa@hampa.ch> *
8
-
* Copyright: (C) 1996-2019 Hampa Hug <hampa@hampa.ch> *
8
+
* Copyright: (C) 1996-2021 Hampa Hug <hampa@hampa.ch> *
9
9
*****************************************************************************/
10
10
11
11
/*****************************************************************************
···
105
105
unsigned short ip;
106
106
unsigned short flg;
107
107
108
-
unsigned short trap_flag;
108
+
unsigned short save_flags;
109
109
110
110
void *mem;
111
111
e86_get_uint8_f mem_get_uint8;
···
153
153
unsigned char state;
154
154
155
155
char irq;
156
-
char enable_int;
157
156
158
157
unsigned int_cnt;
159
158
unsigned char int_vec;
+3
-5
src/cpu/e8086/opcodes.c
+3
-5
src/cpu/e8086/opcodes.c
···
5
5
/*****************************************************************************
6
6
* File name: src/cpu/e8086/opcodes.c *
7
7
* Created: 1996-04-28 by Hampa Hug <hampa@hampa.ch> *
8
-
* Copyright: (C) 1996-2019 Hampa Hug <hampa@hampa.ch> *
8
+
* Copyright: (C) 1996-2021 Hampa Hug <hampa@hampa.ch> *
9
9
*****************************************************************************/
10
10
11
11
/*****************************************************************************
···
496
496
e86_set_ss (c, e86_pop (c));
497
497
e86_set_clk (c, 8);
498
498
499
-
c->enable_int = 0;
499
+
c->save_flags &= ~E86_FLG_I;
500
500
501
501
return (1);
502
502
}
···
2350
2350
e86_pq_init (c);
2351
2351
}
2352
2352
else if (reg == E86_REG_SS) {
2353
-
c->enable_int = 0;
2353
+
c->save_flags &= ~E86_FLG_I;
2354
2354
}
2355
2355
2356
2356
return (c->ea.cnt + 1);
···
3368
3368
e86_set_ip (c, e86_pop (c));
3369
3369
e86_set_cs (c, e86_pop (c));
3370
3370
c->flg = e86_pop (c);
3371
-
3372
-
c->enable_int = 0;
3373
3371
3374
3372
e86_pq_init (c);
3375
3373