M src/gba/gba-bios.c → src/gba/gba-bios.c

@@ -3,6 +3,8 @@
 #include "gba.h"
 #include "gba-memory.h"
 
+static void _unLz77(struct GBAMemory* memory, uint32_t source, uint8_t* dest);
+
 static void _CpuSet(struct GBA* gba) {
 	uint32_t source = gba->cpu.gprs[0];
 	uint32_t dest = gba->cpu.gprs[1];
@@ -78,6 +80,12 @@ break;
 	case 0xC:
 		_FastCpuSet(gba);
 		break;
+	case 0x11:
+		_unLz77(&gba->memory, gba->cpu.gprs[0], &((uint8_t*) gba->memory.wram)[(gba->cpu.gprs[1] & (SIZE_WORKING_RAM - 1))]);
+		break;
+	case 0x12:
+		_unLz77(&gba->memory, gba->cpu.gprs[0], &((uint8_t*) gba->video.renderer->vram)[(gba->cpu.gprs[1] & (SIZE_VRAM - 1))]);
+		break;
 	default:
 		GBALog(GBA_LOG_STUB, "Stub software interrupt: %02x", immediate);
 	}
@@ -86,3 +94,42 @@
 void GBASwi32(struct ARMBoard* board, int immediate) {
 	GBASwi32(board, immediate >> 16);
 }
+
+static void _unLz77(struct GBAMemory* memory, uint32_t source, uint8_t* dest) {
+	int remaining = (GBALoad32(&memory->d, source) & 0xFFFFFF00) >> 8;
+	// We assume the signature byte (0x10) is correct
+	int blockheader;
+	uint32_t sPointer = source + 4;
+	uint8_t* dPointer = dest;
+	int blocksRemaining = 0;
+	int block;
+	uint8_t* disp;
+	int bytes;
+	while (remaining > 0) {
+		if (blocksRemaining) {
+			if (blockheader & 0x80) {
+				// Compressed
+				block = GBALoadU8(&memory->d, sPointer) | (GBALoadU8(&memory->d, sPointer + 1) << 8);
+				sPointer += 2;
+				disp = dPointer - (((block & 0x000F) << 8) | ((block & 0xFF00) >> 8)) - 1;
+				bytes = ((block & 0x00F0) >> 4) + 3;
+				while (bytes-- && remaining) {
+					--remaining;
+					*dPointer = *disp;
+					++disp;
+					++dPointer;
+				}
+			} else {
+				// Uncompressed
+				*dPointer = GBALoadU8(&memory->d, sPointer++);
+				++dPointer;
+				--remaining;
+			}
+			blockheader <<= 1;
+			--blocksRemaining;
+		} else {
+			blockheader = GBALoadU8(&memory->d, sPointer++);
+			blocksRemaining = 8;
+		}
+	}
+}