141 lines
4.2 KiB
C
141 lines
4.2 KiB
C
/* This file is included through vue.c and cannot be built directly. */
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#ifdef VUEAPI
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/* Read bytes from host memory */
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static void busReadBytes(uint8_t *src, uint8_t *dest, uint32_t address,
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uint32_t size, uint32_t length) {
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/* There is no source data */
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if (src == NULL)
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while (length-- > 0)
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*dest++ = 0;
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/* Copy bytes from the source as a circular buffer */
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else for (size--; length-- > 0;)
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*dest++ = src[address++ & size];
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}
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/* Read a value directly from host memory */
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static int32_t busReadMemory(uint8_t *data, uint32_t offset, int type) {
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int32_t value; /* Value read */
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/* There is no source data */
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if (data == NULL)
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return 0;
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/* Locate the value */
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data = &data[offset];
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/* Read the value */
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switch (type) {
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case VUE_S8 : value = *(int8_t *)data; break;
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case VUE_U8 : value = *(uint8_t *)data; break;
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case VUE_S16: value = *(int16_t *)data; break;
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case VUE_U16: value = *(uint16_t *)data; break;
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case VUE_S32: value = *(int32_t *)data; break;
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}
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/* Host memory is big-endian */
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#ifdef VUE_BIGENDIAN
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switch (type) {
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case VUE_S32:
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value = (value >> 16 & 0x0000FFFF) | value << 16;
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/* Fallthrough */
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case VUE_S16:
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case VUE_U16:
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value = (value >> 8 & 0x00FF00FF) | (value << 8 & 0xFF00FF00);
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break;
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}
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#endif
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return value;
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}
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/* Read a value from the CPU bus */
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static int32_t busReadValue(VUE *vue, uint32_t address, int type) {
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address &= -TYPE_SIZES[type];
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switch (address >> 24 & 7) {
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case 1: /* Fallthrough */ /* VSU (write-only) */
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case 3: /* Fallthrough */ /* Unmapped */
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case 4: /* Cartridge expansion (not supported) */
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return 0;
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case 5: /* System WRAM */
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return busReadMemory(vue->bus.wram, address & 0xFFFF, type);
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case 6: return busReadMemory(vue->bus.sram, /* Cartridge RAM */
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address & (vue->bus.sramSize - 1), type);
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case 7: return busReadMemory(vue->bus.rom , /* Cartridge ROM */
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address & (vue->bus.romSize - 1), type);
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}
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return 0; /* Unreachable */
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}
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/* Perform a system reset */
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static void busReset(VUE *vue) {
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int x;
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for (x = 0; x < 0x10000; x++)
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vue->bus.wram[x] = 0;
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}
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/* Write bytes to host memory */
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static void busWriteBytes(uint8_t *dest, uint8_t *src, uint32_t address,
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uint32_t size, uint32_t length) {
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if (dest != NULL)
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for (size--; length-- > 0;)
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dest[address++ & size] = *src++;
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}
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/* Write a value directly to host memory */
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static void busWriteMemory(uint8_t *data, uint32_t offset, int type,
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int32_t value) {
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/* There is no destination data */
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if (data == NULL)
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return;
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/* Locate the value */
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data = &data[offset];
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/* Host memory is big-endian */
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#ifdef VUE_BIGENDIAN
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switch (type) {
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case VUE_S32:
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value = (value >> 16 & 0x0000FFFF) | value << 16;
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/* Fallthrough */
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case VUE_S16:
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case VUE_U16:
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value = (value >> 8 & 0x00FF00FF) | (value << 8 & 0xFF00FF00);
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break;
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}
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#endif
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/* Write the value */
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switch (type) {
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case VUE_S8 : /* Fallthrough */
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case VUE_U8 : *(uint8_t *)data = (uint8_t) value; break;
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case VUE_S16: /* Fallthrough */
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case VUE_U16: *(uint16_t *)data = (int16_t) value; break;
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case VUE_S32: *(int32_t *)data = (int32_t) value; break;
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}
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}
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/* Write a value to the CPU bus */
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static void busWriteValue(VUE *vue, uint32_t address, int type, int32_t value){
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address &= -TYPE_SIZES[type];
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switch (address >> 24 & 7) {
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case 5: /* System WRAM */
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busWriteMemory(vue->bus.wram, address & 0xFFFF, type, value);
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break;
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case 6: /* Cartridge RAM */
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busWriteMemory(vue->bus.sram,
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address & (vue->bus.sramSize - 1), type, value);
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break;
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case 7: /* Cartridge ROM */
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busWriteMemory(vue->bus.rom ,
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address & (vue->bus.romSize - 1), type, value);
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break;
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}
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}
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#endif /* VUEAPI */
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