Hack to improve timers used as counter

Fixes smashing drive running too fast Improves Bibi und Tina a bit, but still has problems (uses cascade)
Gericom · Apr 12, 2020 · bb15d71 · bb15d71
1 parent 08ec54a
commit bb15d71
Show file tree

Hide file tree

Showing 3 changed files with 57 additions and 7 deletions.
diff --git a/arm9/source/dtcm_data.s b/arm9/source/dtcm_data.s
@@ -309,6 +309,12 @@ timer_shadow_regs_dtcm:
 	.short 0 //reload value
 .endr
 
+.global timer_shadow_regs_count_dtcm
+timer_shadow_regs_count_dtcm:
+.rept 4
+	.short 0 //counter value
+.endr
+
 //the current bios opcode that is returned if you do a protected read
 //[00DCh+8] = 0xE129F000, after startup and softreset //before this address 0x27C is read
 //[0134h+8] = 0xE25EF004, during irq execution

diff --git a/arm9/source/emu/timer.s b/arm9/source/emu/timer.s
@@ -8,26 +8,60 @@
 
 ADDRESS_TIMER_BASE = 0x04000100
 
-.macro fix_timer_counter_read regb, rega
-	mov \regb, \rega, lsl #16
+// .macro fix_timer_counter_read regb, rega
+// 	mov \regb, \rega, lsl #16
+// 	tst \rega, #(4 << 16)
+// 	movne \regb, \regb, lsr #16 //if slave mode, don't divide by 2
+// 	moveq \regb, \regb, lsr #17 //if normal mode, fix timer value
+// 	orreq \regb, \regb, #0x8000 //set top bit as we assume this bit was 1 (we don't really have a proper way of fixing that)
+// .endm
+
+.macro fix_timer_counter_read regb, rega, regc
 	tst \rega, #(4 << 16)
-	movne \regb, \regb, lsr #16 //if slave mode, don't divide by 2
-	moveq \regb, \regb, lsr #17 //if normal mode, fix timer value
-	orreq \regb, \regb, #0x8000 //set top bit as we assume this bit was 1 (we don't really have a proper way of fixing that)
+	mov \regb, \rega, lsl #16
+		movne \regb, \regb, lsr #16 //if slave mode, don't divide by 2
+		bne 1f
+	mov \regb, \regb, lsr #17 //if normal mode, fix timer value
+	tst \regc, #0x8000
+		orrne \regb, #0x8000
+	cmp \regb, \regc
+		eorlt \regb, #0x8000
+1:
 .endm
 
 .global read_address_timer_counter
 read_address_timer_counter:
 	ldr r10, [r9] //read full info
-	fix_timer_counter_read r10, r10
+
+	ldr r12,= ADDRESS_TIMER_BASE
+	ldr r13,= timer_shadow_regs_count_dtcm
+	sub r12, r9, r12
+	add r13, r12, lsr #1
+	ldrh r11, [r13]
+
+	fix_timer_counter_read r10, r10, r11
+
+	strh r10, [r13]
+
 	//ldrh r10, [r9]
 	//mov r10, r10, lsr #1
 	bx lr
 
 .global read_address_timer
 read_address_timer:
 	ldr r10, [r9]
-	fix_timer_counter_read r12, r10
+
+
+	ldr r12,= ADDRESS_TIMER_BASE
+	ldr r13,= timer_shadow_regs_count_dtcm
+	sub r12, r9, r12
+	add r13, r12, lsr #1
+	ldrh r11, [r13]
+
+	fix_timer_counter_read r12, r10, r11
+
+	strh r12, [r13]
+
 	mov r10, r10, lsr #16
 	orr r10, r12, r10, lsl #16
 	//mov r12, r10, lsr #16

diff --git a/arm9/source/gamePatches.vram.cpp b/arm9/source/gamePatches.vram.cpp
@@ -173,6 +173,16 @@ void gptc_patchRom()
 		*(u32*)(MAIN_MEMORY_ADDRESS_ROM_DATA + 0x3D73C0) = 0xE3A0001B;
 		*(u32*)(MAIN_MEMORY_ADDRESS_ROM_DATA + 0x3D73FC) = 0xE3A0009B;
 	}
+	else if(gameCode == 0x50565342)
+	{
+		//Smashing Drive (Europe) (En,Fr,De,Es,It)
+		*(u32*)(MAIN_MEMORY_ADDRESS_ROM_DATA + 0x7F4C2C) = 0xE8990E00;
+	}
+	else if(gameCode == 0x45565342)
+	{
+		//Smashing Drive (USA)
+		*(u32*)(MAIN_MEMORY_ADDRESS_ROM_DATA + 0x7F62B8) = 0xE8990E00;
+	}
 #endif
 	/*else if(gameCode == 0x45573241 || gameCode == 0x50573241)
 	{