+ struct PicoVideo *pv = &Pico.video;
+ unsigned char d;
+
+ d = PicoMem.vramb[pv->addr];
+ pv->addr = (pv->addr + 1) & 0x3fff;
+ pv->pending = 0;
+ return d;
+}
+
+static unsigned char vdp_ctl_read(void)
+{
+ unsigned char d = Pico.video.pending_ints << 7;
+ Pico.video.pending = 0;
+ Pico.video.pending_ints = 0;
+
+ elprintf(EL_SR, "VDP sr: %02x", d);
+ return d;
+}
+
+static void vdp_data_write(unsigned char d)
+{
+ struct PicoVideo *pv = &Pico.video;
+
+ if (pv->type == 3) {
+ PicoMem.cram[pv->addr & 0x1f] = d;
+ Pico.m.dirtyPal = 1;
+ } else {
+ PicoMem.vramb[pv->addr] = d;
+ }
+ pv->addr = (pv->addr + 1) & 0x3fff;
+
+ pv->pending = 0;
+}
+
+static void vdp_ctl_write(unsigned char d)
+{
+ struct PicoVideo *pv = &Pico.video;
+
+ if (pv->pending) {
+ if ((d >> 6) == 2) {
+ pv->reg[d & 0x0f] = pv->addr;
+ elprintf(EL_IO, " VDP r%02x=%02x", d & 0x0f, pv->addr & 0xff);
+ }
+ pv->type = d >> 6;
+ pv->addr &= 0x00ff;
+ pv->addr |= (d & 0x3f) << 8;
+ } else {
+ pv->addr &= 0x3f00;
+ pv->addr |= d;
+ }
+ pv->pending ^= 1;
+}
+
+static unsigned char z80_sms_in(unsigned short a)
+{
+ unsigned char d = 0;
+
+ elprintf(EL_IO, "z80 port %04x read", a);
+ a &= 0xc1;
+ switch (a)
+ {
+ case 0x00:
+ case 0x01:
+ d = 0xff;
+ break;
+
+ case 0x40: /* V counter */
+ d = Pico.video.v_counter;
+ elprintf(EL_HVCNT, "V counter read: %02x", d);
+ break;
+
+ case 0x41: /* H counter */
+ d = Pico.m.rotate++;
+ elprintf(EL_HVCNT, "H counter read: %02x", d);
+ break;
+
+ case 0x80:
+ d = vdp_data_read();
+ break;
+
+ case 0x81:
+ d = vdp_ctl_read();
+ break;
+
+ case 0xc0: /* I/O port A and B */
+ d = ~((PicoPad[0] & 0x3f) | (PicoPad[1] << 6));
+ break;
+
+ case 0xc1: /* I/O port B and miscellaneous */
+ d = (Pico.ms.io_ctl & 0x80) | ((Pico.ms.io_ctl << 1) & 0x40) | 0x30;
+ d |= ~(PicoPad[1] >> 2) & 0x0f;
+ break;
+ }
+
+ elprintf(EL_IO, "ret = %02x", d);
+ return d;
+}
+
+static void z80_sms_out(unsigned short a, unsigned char d)
+{
+ elprintf(EL_IO, "z80 port %04x write %02x", a, d);
+ a &= 0xc1;
+ switch (a)
+ {
+ case 0x01:
+ Pico.ms.io_ctl = d;
+ break;
+
+ case 0x40:
+ case 0x41:
+ if (PicoOpt & POPT_EN_PSG)
+ SN76496Write(d);
+ break;
+
+ case 0x80:
+ vdp_data_write(d);
+ break;
+
+ case 0x81:
+ vdp_ctl_write(d);
+ break;
+ }