GBA BIOS: Implement SoftReset

CHANGES

@@ -14,7 +14,7 @@ Features:
  - Support for games using the tilt sensor
  - Remappable shortcuts for keyboard and gamepad
  - Rewinding of emulation
- - Implemented BIOS routines RegisterRamReset, Diff8bitUnFilterWram, Diff8bitUnFilterVram, and Diff16bitUnFilter
+ - Implemented BIOS routines SoftReset, RegisterRamReset, Diff8bitUnFilterWram, Diff8bitUnFilterVram, and Diff16bitUnFilter
 Bugfixes:
  - Qt: Fix issue with set frame sizes being the wrong height
  - Qt: Fix emulator crashing when full screen if a game is not running

src/gba/gba-bios.c

@@ -8,6 +8,7 @@
 #include "gba.h"
 #include "gba-io.h"
 #include "gba-memory.h"
+#include "isa-inlines.h"
 
 const uint32_t GBA_BIOS_CHECKSUM = 0xBAAE187F;
 const uint32_t GBA_DS_BIOS_CHECKSUM = 0xBAAE1880;
@@ -17,6 +18,31 @@ static void _unHuffman(struct GBA* gba);
 static void _unRl(struct GBA* gba, int width);
 static void _unFilter(struct GBA* gba, int inwidth, int outwidth);
 
+static void _SoftReset(struct GBA* gba) {
+	struct ARMCore* cpu = gba->cpu;
+	ARMSetPrivilegeMode(cpu, MODE_IRQ);
+	cpu->spsr.packed = 0;
+	cpu->gprs[ARM_LR] = 0;
+	cpu->gprs[ARM_SP] = SP_BASE_IRQ;
+	ARMSetPrivilegeMode(cpu, MODE_SUPERVISOR);
+	cpu->spsr.packed = 0;
+	cpu->gprs[ARM_LR] = 0;
+	cpu->gprs[ARM_SP] = SP_BASE_SUPERVISOR;
+	ARMSetPrivilegeMode(cpu, MODE_SYSTEM);
+	cpu->gprs[ARM_LR] = 0;
+	cpu->gprs[ARM_SP] = SP_BASE_SYSTEM;
+	int8_t flag = ((int8_t*) gba->memory.iwram)[0x7FFA];
+	memset(((int8_t*) gba->memory.iwram) + SIZE_WORKING_IRAM - 0x200, 0, 0x200);
+	if (flag) {
+		cpu->gprs[ARM_PC] = BASE_WORKING_RAM;
+	} else {
+		cpu->gprs[ARM_PC] = BASE_CART0;
+	}
+	_ARMSetMode(cpu, MODE_ARM);
+	int currentCycles = 0;
+	ARM_WRITE_PC;
+}
+
 static void _RegisterRamReset(struct GBA* gba) {
 	uint32_t registers = gba->cpu->gprs[0];
 	struct ARMCore* cpu = gba->cpu;
@@ -156,6 +182,9 @@ void GBASwi16(struct ARMCore* cpu, int immediate) {
 		return;
 	}
 	switch (immediate) {
+	case 0x0:
+		_SoftReset(gba);
+		break;
 	case 0x1:
 		_RegisterRamReset(gba);
 		break;

src/gba/gba.c

@@ -24,12 +24,6 @@ const uint32_t GBA_COMPONENT_MAGIC = 0x1000000;
 static const size_t GBA_ROM_MAGIC_OFFSET = 2;
 static const uint8_t GBA_ROM_MAGIC[] = { 0x00, 0xEA };
 
-enum {
-	SP_BASE_SYSTEM = 0x03FFFF00,
-	SP_BASE_IRQ = 0x03FFFFA0,
-	SP_BASE_SUPERVISOR = 0x03FFFFE0
-};
-
 struct GBACartridgeOverride {
 	const char id[4];
 	enum SavedataType type;

src/gba/gba.h

@@ -75,6 +75,12 @@ enum GBAComponent {
 	GBA_COMPONENT_MAX
 };
 
+enum {
+	SP_BASE_SYSTEM = 0x03007F00,
+	SP_BASE_IRQ = 0x03007FA0,
+	SP_BASE_SUPERVISOR = 0x03007FE0
+};
+
 struct GBA;
 struct GBARotationSource;
 struct Patch;