mirror of
https://github.com/hsoft/collapseos.git
synced 2024-11-27 17:18:05 +11:00
d1718a90c7
Because that mode behaves exactly like in a regular TMS9918, a new driver for TMS9918 has been added in blkfs and SMS' VDP now uses it. Also, fix broken 5x7 font.
86 lines
2.4 KiB
C
86 lines
2.4 KiB
C
#include <string.h>
|
|
#include "sms_vdp.h"
|
|
|
|
static bool _is_mode4(VDP *vdp)
|
|
{
|
|
return (vdp->tms.regs[0]&0x4);
|
|
}
|
|
|
|
void vdp_init(VDP *vdp)
|
|
{
|
|
tms_init(&vdp->tms);
|
|
memset(vdp->cram, 0, VDP_CRAM_SIZE);
|
|
}
|
|
|
|
void vdp_cmd_wr(VDP *vdp, uint8_t val)
|
|
{
|
|
if (!vdp->tms.has_cmdlsb) {
|
|
tms_cmd_wr(&vdp->tms, val);
|
|
} else {
|
|
if ((val & 0xc0) == 0xc0) {
|
|
// palette RAM
|
|
// curaddr > VRAM == addr in CRAM
|
|
vdp->tms.curaddr = TMS_VRAM_SIZE + (vdp->tms.cmdlsb&0x1f);
|
|
} else {
|
|
tms_cmd_wr(&vdp->tms, val);
|
|
vdp->tms.width = _is_mode4(vdp) ? 32*8 : 40*6;
|
|
}
|
|
}
|
|
}
|
|
|
|
uint8_t vdp_data_rd(VDP *vdp)
|
|
{
|
|
TMS9918 *tms = &vdp->tms;
|
|
if (tms->curaddr < TMS_VRAM_SIZE) {
|
|
return tms_data_rd(&vdp->tms);
|
|
} else if (tms->curaddr - TMS_VRAM_SIZE < VDP_CRAM_SIZE) {
|
|
return vdp->cram[tms->curaddr++-TMS_VRAM_SIZE];
|
|
} else {
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
void vdp_data_wr(VDP *vdp, uint8_t val)
|
|
{
|
|
TMS9918 *tms = &vdp->tms;
|
|
if (tms->curaddr < TMS_VRAM_SIZE) {
|
|
tms_data_wr(&vdp->tms, val);
|
|
} else if (tms->curaddr - TMS_VRAM_SIZE < VDP_CRAM_SIZE) {
|
|
vdp->cram[tms->curaddr++-TMS_VRAM_SIZE] = val;
|
|
}
|
|
}
|
|
|
|
uint8_t vdp_pixel(VDP *vdp, uint16_t x, uint16_t y)
|
|
{
|
|
TMS9918 *tms = &vdp->tms;
|
|
if (!_is_mode4(vdp)) {
|
|
return tms_pixel(tms, x, y);
|
|
}
|
|
if (x >= tms->width) {
|
|
return 0;
|
|
}
|
|
if (y >= tms->height) {
|
|
return 0;
|
|
}
|
|
// name table offset
|
|
uint16_t offset = (tms->regs[2] & 0xe) << 10;
|
|
offset += ((y/8) << 6) + ((x/8) << 1);
|
|
uint16_t tableval = tms->vram[offset] + (tms->vram[offset+1] << 8);
|
|
uint16_t tilenum = tableval & 0x1ff;
|
|
// is palette select bit on? if yes, use sprite palette instead
|
|
uint8_t palettemod = tableval & 0x800 ? 0x10 : 0;
|
|
// tile offset this time. Each tile is 0x20 bytes long.
|
|
offset = tilenum * 0x20;
|
|
// Each 4 byte is a row. Find row first.
|
|
offset += ((y%8) * 4);
|
|
uint8_t bitnum = 7 - (x%8);
|
|
// Now, let's compose the result by pushing the right bit of our 4 bytes
|
|
// into our result.
|
|
uint8_t palette_id = ((tms->vram[offset] >> bitnum) & 1) + \
|
|
(((tms->vram[offset+1] >> bitnum) & 1) << 1) + \
|
|
(((tms->vram[offset+2] >> bitnum) & 1) << 2) + \
|
|
(((tms->vram[offset+3] >> bitnum) & 1) << 3);
|
|
uint8_t rgb = vdp->cram[palettemod+palette_id];
|
|
return rgb;
|
|
}
|