src/libultra/io/pirawdma.c


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#include "ultra64.h"

s32 __osPiRawStartDma(s32 direction, uintptr_t devAddr, void* dramAddr, size_t size) {
    register int status = IO_READ(PI_STATUS_REG);

    while (status & (PI_STATUS_IO_BUSY | PI_STATUS_DMA_BUSY)) {
        status = IO_READ(PI_STATUS_REG);
    }

    IO_WRITE(PI_DRAM_ADDR_REG, osVirtualToPhysical(dramAddr));

    IO_WRITE(PI_CART_ADDR_REG, K1_TO_PHYS((uintptr_t)osRomBase | devAddr));

    switch (direction) {
        case OS_READ:
            IO_WRITE(PI_WR_LEN_REG, size - 1);
            break;

        case OS_WRITE:
            IO_WRITE(PI_RD_LEN_REG, size - 1);
            break;

        default:
            return -1;
    }
    return 0;
}