1#include "gba-bios.h"
  2
  3#include "gba.h"
  4#include "gba-io.h"
  5#include "gba-memory.h"
  6
  7#include <math.h>
  8#include <stdlib.h>
  9
 10static void _unLz77(struct GBAMemory* memory, uint32_t source, uint8_t* dest);
 11
 12static void _RegisterRamReset(struct GBA* gba) {
 13	uint32_t registers = gba->cpu.gprs[0];
 14	(void)(registers);
 15	GBALog(GBA_LOG_STUB, "RegisterRamReset unimplemented");
 16}
 17
 18static void _CpuSet(struct GBA* gba) {
 19	uint32_t source = gba->cpu.gprs[0];
 20	uint32_t dest = gba->cpu.gprs[1];
 21	uint32_t mode = gba->cpu.gprs[2];
 22	int count = mode & 0x000FFFFF;
 23	int fill = mode & 0x01000000;
 24	int wordsize = (mode & 0x04000000) ? 4 : 2;
 25	int i;
 26	if (fill) {
 27		if (wordsize == 4) {
 28			source &= 0xFFFFFFFC;
 29			dest &= 0xFFFFFFFC;
 30			int32_t word = GBALoad32(&gba->memory.d, source);
 31			for (i = 0; i < count; ++i) {
 32				GBAStore32(&gba->memory.d, dest + (i << 2), word);
 33			}
 34		} else {
 35			source &= 0xFFFFFFFE;
 36			dest &= 0xFFFFFFFE;
 37			uint16_t word = GBALoad16(&gba->memory.d, source);
 38			for (i = 0; i < count; ++i) {
 39				GBAStore16(&gba->memory.d, dest + (i << 1), word);
 40			}
 41		}
 42	} else {
 43		if (wordsize == 4) {
 44			source &= 0xFFFFFFFC;
 45			dest &= 0xFFFFFFFC;
 46			for (i = 0; i < count; ++i) {
 47				int32_t word = GBALoad32(&gba->memory.d, source + (i << 2));
 48				GBAStore32(&gba->memory.d, dest + (i << 2), word);
 49			}
 50		} else {
 51			source &= 0xFFFFFFFE;
 52			dest &= 0xFFFFFFFE;
 53			for (i = 0; i < count; ++i) {
 54				uint16_t word = GBALoad16(&gba->memory.d, source + (i << 1));
 55				GBAStore16(&gba->memory.d, dest + (i << 1), word);
 56			}
 57		}
 58	}
 59}
 60
 61static void _FastCpuSet(struct GBA* gba) {
 62	uint32_t source = gba->cpu.gprs[0] & 0xFFFFFFFC;
 63	uint32_t dest = gba->cpu.gprs[1] & 0xFFFFFFFC;
 64	uint32_t mode = gba->cpu.gprs[2];
 65	int count = mode & 0x000FFFFF;
 66	count = ((count + 7) >> 3) << 3;
 67	int i;
 68	if (mode & 0x01000000) {
 69		int32_t word = GBALoad32(&gba->memory.d, source);
 70		for (i = 0; i < count; ++i) {
 71			GBAStore32(&gba->memory.d, dest + (i << 2), word);
 72		}
 73	} else {
 74		for (i = 0; i < count; ++i) {
 75			int32_t word = GBALoad32(&gba->memory.d, source + (i << 2));
 76			GBAStore32(&gba->memory.d, dest + (i << 2), word);
 77		}
 78	}
 79}
 80
 81static void _MidiKey2Freq(struct GBA* gba) {
 82	uint32_t key = GBALoad32(&gba->memory.d, gba->cpu.gprs[0] + 4);
 83	gba->cpu.gprs[0] = key / powf(2, (180.f - gba->cpu.gprs[1] - gba->cpu.gprs[2] / 256.f) / 12.f);
 84}
 85
 86void GBASwi16(struct ARMBoard* board, int immediate) {
 87	struct GBA* gba = ((struct GBABoard*) board)->p;
 88	switch (immediate) {
 89	case 0x1:
 90		_RegisterRamReset(gba);
 91		break;
 92	case 0x2:
 93		GBAHalt(gba);
 94		break;
 95	case 0x05:
 96		// VBlankIntrWait
 97		gba->cpu.gprs[0] = 1;
 98		gba->cpu.gprs[1] = 1;
 99		// Fall through:
100	case 0x04:
101		// IntrWait
102		gba->memory.io[REG_IME >> 1] = 1;
103		if (!gba->cpu.gprs[0] && gba->memory.io[REG_IF >> 1] & gba->cpu.gprs[1]) {
104			break;
105		}
106		gba->memory.io[REG_IF >> 1] = 0;
107		ARMRaiseSWI(&gba->cpu);
108		break;
109	case 0x6:
110		{
111			div_t result = div(gba->cpu.gprs[0], gba->cpu.gprs[1]);
112			gba->cpu.gprs[0] = result.quot;
113			gba->cpu.gprs[1] = result.rem;
114			gba->cpu.gprs[2] = abs(result.quot);
115		}
116		break;
117	case 0x7:
118		{
119			div_t result = div(gba->cpu.gprs[1], gba->cpu.gprs[0]);
120			gba->cpu.gprs[0] = result.quot;
121			gba->cpu.gprs[1] = result.rem;
122			gba->cpu.gprs[2] = abs(result.quot);
123		}
124		break;
125	case 0xB:
126		_CpuSet(gba);
127		break;
128	case 0xC:
129		_FastCpuSet(gba);
130		break;
131	case 0x11:
132	case 0x12:
133		switch (gba->cpu.gprs[1] >> BASE_OFFSET) {
134			case REGION_WORKING_RAM:
135				_unLz77(&gba->memory, gba->cpu.gprs[0], &((uint8_t*) gba->memory.wram)[(gba->cpu.gprs[1] & (SIZE_WORKING_RAM - 1))]);
136				break;
137			case REGION_VRAM:
138				_unLz77(&gba->memory, gba->cpu.gprs[0], &((uint8_t*) gba->video.vram)[(gba->cpu.gprs[1] & 0x0001FFFF)]);
139				break;
140			default:
141				GBALog(GBA_LOG_WARN, "Bad LZ77 destination");
142				break;
143		}
144		break;
145	case 0x1F:
146		_MidiKey2Freq(gba);
147		break;
148	default:
149		GBALog(GBA_LOG_STUB, "Stub software interrupt: %02x", immediate);
150	}
151}
152
153void GBASwi32(struct ARMBoard* board, int immediate) {
154	GBASwi16(board, immediate >> 16);
155}
156
157static void _unLz77(struct GBAMemory* memory, uint32_t source, uint8_t* dest) {
158	int remaining = (GBALoad32(&memory->d, source) & 0xFFFFFF00) >> 8;
159	// We assume the signature byte (0x10) is correct
160	int blockheader;
161	uint32_t sPointer = source + 4;
162	uint8_t* dPointer = dest;
163	int blocksRemaining = 0;
164	int block;
165	uint8_t* disp;
166	int bytes;
167	while (remaining > 0) {
168		if (blocksRemaining) {
169			if (blockheader & 0x80) {
170				// Compressed
171				block = GBALoadU8(&memory->d, sPointer) | (GBALoadU8(&memory->d, sPointer + 1) << 8);
172				sPointer += 2;
173				disp = dPointer - (((block & 0x000F) << 8) | ((block & 0xFF00) >> 8)) - 1;
174				bytes = ((block & 0x00F0) >> 4) + 3;
175				while (bytes-- && remaining) {
176					--remaining;
177					*dPointer = *disp;
178					++disp;
179					++dPointer;
180				}
181			} else {
182				// Uncompressed
183				*dPointer = GBALoadU8(&memory->d, sPointer++);
184				++dPointer;
185				--remaining;
186			}
187			blockheader <<= 1;
188			--blocksRemaining;
189		} else {
190			blockheader = GBALoadU8(&memory->d, sPointer++);
191			blocksRemaining = 8;
192		}
193	}
194}