[NSF] Refined NMI interception (#386).

punesemu · Mar 19, 2024 · b6dc62f · b6dc62f
1 parent a51c9f4
commit b6dc62f
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Showing 5 changed files with 6 additions and 9 deletions.
diff --git a/src/core/cpu.c b/src/core/cpu.c
@@ -977,8 +977,8 @@ void cpu_exe_op(BYTE nidx) {
 		}
 		nes[nidx].c.cpu.cycles = 0;
 		break;
-	case 0x100: IMP(RD_OP, NMI) break;                                                           // NMI
-	case 0x200: IMP(RD_OP, IRQ(nes[nidx].c.cpu.SR & 0xEF)) break;                                // IRQ
+	case OP_NMI: IMP(RD_OP, NMI) break;                                                          // NMI
+	case OP_IRQ: IMP(RD_OP, IRQ(nes[nidx].c.cpu.SR & 0xEF)) break;                               // IRQ
 	}
 
 	// se presenti eseguo i restanti cicli di PPU e APU

diff --git a/src/core/cpu.h b/src/core/cpu.h
@@ -27,6 +27,8 @@ enum interrupt_types {
 	INT_NMI = 0xFFFA,
 	INT_RESET = 0xFFFC,
 	INT_IRQ = 0xFFFE,
+	OP_NMI = 0x100,
+	OP_IRQ = 0x200,
 	APU_IRQ = 0x01,
 	DMC_IRQ = 0x02,
 	EXT_IRQ = 0x04,

diff --git a/src/core/cpu_inline.h b/src/core/cpu_inline.h
@@ -475,15 +475,14 @@ INLINE static void nsf_rd_mem(BYTE nidx, WORD address, BYTE made_tick) {
 				if (nsf.state & NSF_CHANGE_SONG) {
 					nes[nidx].c.cpu.openbus = NSF_ROUTINE_NSF_INIT & 0xFF;
 					return;
-				} else if (nsf.nmi.exec) {
+				} else if (nes[nidx].c.cpu.opcode == OP_NMI) {
 					nes[nidx].c.cpu.openbus = NSF_ROUTINE_NMI & 0xFF;
 					return;
 				}
 				break;
 			case 0xFFFB:
-				if ((nsf.state & NSF_CHANGE_SONG) || nsf.nmi.exec) {
+				if ((nsf.state & NSF_CHANGE_SONG) || (nes[nidx].c.cpu.opcode == OP_NMI)) {
 					nes[nidx].c.cpu.openbus = NSF_ROUTINE_START >> 8;
-					nsf.nmi.exec = FALSE;
 					return;
 				}
 				break;

diff --git a/src/core/mappers/mapper_NSF.c b/src/core/mappers/mapper_NSF.c
@@ -80,7 +80,6 @@ void map_init_NSF(void) {
 	select_region_NSF();
 	nsf.rate.count = nsf.rate.reload;
 	nsf.nmi.count = nsf.rate.reload;
-	nsf.nmi.exec = FALSE;
 	nsf.nmi.in_use = FALSE;
 
 	nsf.adr.loop = NSF_ROUTINE_LOOP;
@@ -130,7 +129,6 @@ BYTE extcl_save_mapper_NSF(BYTE mode, BYTE slot, FILE *fp) {
 
 	save_slot_ele(mode, slot, nsf.rate.count);
 
-	save_slot_ele(mode, slot, nsf.nmi.exec);
 	save_slot_ele(mode, slot, nsf.nmi.in_use);
 	save_slot_ele(mode, slot, nsf.nmi.count);
 
@@ -221,7 +219,6 @@ void extcl_cpu_every_cycle_NSF(BYTE nidx) {
 		nsf.nmi.count = nsf.nmi.reload;
 
 		nes[0].c.nmi.high = !nsf.nmi.in_use;
-		nsf.nmi.exec = nes[0].c.nmi.high;
 		nes[0].p.ppu.odd_frame = !nes[0].p.ppu.odd_frame;
 		nes[0].p.ppu.frames++;
 

diff --git a/src/core/nsf.h b/src/core/nsf.h
@@ -110,7 +110,6 @@ typedef struct _nsf {
 		DBWORD reload;
 	} rate;
 	struct _nsf_nmi {
-		BYTE exec;
 		BYTE in_use;
 		DBWORD count;
 		DBWORD reload;