shithub: psxe

ref: cb7d802d87208da493cc31a0ea9fab22f4472637
dir: /psx/dev/bios.c/

#include "dev/bios.h"
#include "log.h"

#include "p9.h"

static int
psx_readn_fd(int fd, void* buf, uint32_t size)
{
    uint8_t* p = (uint8_t*)buf;
    uint32_t n = size;

    while (n) {
        long r = read(fd, p, n);

        if (r <= 0)
            return -1;

        p += r;
        n -= r;
    }

    return 0;
}

psx_bios_t* psx_bios_create(void) {
    return (psx_bios_t*)malloc(sizeof(psx_bios_t));
}

void psx_bios_init(psx_bios_t* bios) {
    memset(bios, 0, sizeof(psx_bios_t));

    bios->io_base = PSX_BIOS_BEGIN;
    bios->io_size = PSX_BIOS_SIZE;
    bios->bus_delay = 18;
}

int psx_bios_load(psx_bios_t* bios, const char* path) {
    if (!path)
        return 0;

    int fd = open(path, OREAD);
    vlong size;

    if (fd < 0)
        return 1;

    // Almost all PS1 BIOS ROMs are 512 KiB in size.
    // There's (at least) one exception, and that is SCPH-5903.
    // This is a special asian model PS1 that had built-in support
    // for Video CD (VCD) playback. Its BIOS is double the normal
    // size
    size = seek(fd, 0, 2);
    if (size <= 0) {
        close(fd);
        return 2;
    }

    if (seek(fd, 0, 0) < 0) {
        close(fd);
        return 2;
    }

    bios->buf = malloc(size);
    if (!bios->buf) {
        close(fd);
        return 2;
    }
    bios->io_size = size;

    if (psx_readn_fd(fd, bios->buf, size) < 0) {
        close(fd);
        return 2;
    }

    close(fd);

    return 0;
}

uint32_t psx_bios_read32(psx_bios_t* bios, uint32_t offset) {
    return *((uint32_t*)(bios->buf + offset));
}

uint16_t psx_bios_read16(psx_bios_t* bios, uint32_t offset) {
    return *((uint16_t*)(bios->buf + offset));
}

uint8_t psx_bios_read8(psx_bios_t* bios, uint32_t offset) {
    return bios->buf[offset];
}

void psx_bios_write32(psx_bios_t* bios, uint32_t offset, uint32_t value) {
    USED(bios);
    log_warn("Unhandled 32-bit BIOS write at offset %08x (%08x)", offset, value);
}

void psx_bios_write16(psx_bios_t* bios, uint32_t offset, uint16_t value) {
    USED(bios);
    log_warn("Unhandled 16-bit BIOS write at offset %08x (%04x)", offset, value);
}

void psx_bios_write8(psx_bios_t* bios, uint32_t offset, uint8_t value) {
    USED(bios);
    log_warn("Unhandled 8-bit BIOS write at offset %08x (%02x)", offset, value);
}

void psx_bios_destroy(psx_bios_t* bios) {
    free(bios->buf);
    free(bios);
}