shithub: sms

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Allow tidx to be >= 0x100

--- a/vdp.c

+++ b/vdp.c

@@ -8,11 +8,12 @@

 uint8_t vdpcode, vdpstat = 0;

 uint16_t vdpaddr;

 uint8_t vdpbuf;

-int vdpx = 0, vdpy, vdpyy, frame, intla;

+int vdpx = 0, vdpyy, frame, intla;

 int first = 1;

 uint16_t hctr;

 static int xmax, xdisp;

 enum { ymax = 262, yvbl = 234 };

+int vdpy = ymax-1;

 void

 vdpmode(void)

@@ -50,13 +51,16 @@

 	int txoff = x & 7;

 	uint16_t taddr = screenmap + (((ty << 5) + tx) << 1);

-	int tidx = vram[taddr];

-	int info = vram[taddr + 1];

+	uint16_t tidx = vram[taddr];

+	uint8_t info = vram[taddr + 1];

-	int hflip = (info & 1 << 1) != 0;

-	int vflip = (info & 1 << 2) != 0;

-	int paloff = (info & 1 << 3) != 0 ? 16 : 0;

+	if ((info & 1) != 0)

+		tidx = (tidx | 0x100) & 0x1ff;

+	uint8_t hflip = (info & 1 << 1) != 0;

+	uint8_t vflip = (info & 1 << 2) != 0;

+	uint8_t paloff = (info & 1 << 3) != 0 ? 16 : 0;

+

 	int data = (tidx << 5) + ((vflip ? 7 - tyoff : tyoff) << 2);

 	int xx = hflip ? txoff : 7 - txoff;

@@ -212,7 +216,9 @@

 uint8_t

 vdpvcounter(void)

 {

-	// printf("    vdp read vcounter %x\n", vdpy);

+	// printf("    vdp read hcounter %y\n", vdpy);

+	if (vdpy > 0xda)

+		return vdpy - 0x06;

 	return vdpy;

 }

-- 

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