mirror of
https://github.com/ekeeke/Genesis-Plus-GX.git
synced 2024-11-10 04:45:08 +01:00
49 lines
1.2 KiB
C
49 lines
1.2 KiB
C
// The SVP chip emulator
|
|
|
|
// (c) Copyright 2008, Grazvydas "notaz" Ignotas
|
|
// Free for non-commercial use.
|
|
|
|
// For commercial use, separate licencing terms must be obtained.
|
|
|
|
/* SVP Controller */
|
|
/* modified for Genesis Plus GCN port (eke-eke) */
|
|
|
|
#include "shared.h"
|
|
|
|
svp_t *svp = NULL;
|
|
uint16 SVP_cycles = 850;
|
|
|
|
void svp_init(void)
|
|
{
|
|
svp = (void *) ((char *)cart_rom + 0x200000);
|
|
memset(svp, 0, sizeof(*svp));
|
|
}
|
|
|
|
void svp_reset(void)
|
|
{
|
|
memcpy(svp->iram_rom + 0x800, cart_rom + 0x800, 0x20000 - 0x800);
|
|
ssp1601_reset(&svp->ssp1601);
|
|
}
|
|
|
|
void svp_write_dram(uint32 address, uint32 data)
|
|
{
|
|
*(uint16 *)(svp->dram + (address & 0x1fffe)) = data;
|
|
if ((address == 0x30fe06) && data) svp->ssp1601.emu_status &= ~SSP_WAIT_30FE06;
|
|
if ((address == 0x30fe08) && data) svp->ssp1601.emu_status &= ~SSP_WAIT_30FE08;
|
|
}
|
|
|
|
uint32 svp_read_cell_1(uint32 address)
|
|
{
|
|
address >>= 1;
|
|
address = (address & 0x7001) | ((address & 0x3e) << 6) | ((address & 0xfc0) >> 5);
|
|
return *(uint16 *)(svp->dram + (address & 0x1fffe));
|
|
}
|
|
|
|
uint32 svp_read_cell_2(uint32 address)
|
|
{
|
|
address >>= 1;
|
|
address = (address & 0x7801) | ((address & 0x1e) << 6) | ((address & 0x7e0) >> 4);
|
|
return *(uint16 *)(svp->dram + (address & 0x1fffe));
|
|
}
|
|
|