32x: packed pixel mode (works over 68k)

[picodrive.git] / pico / 32x / draw.c

diff --git a/pico/32x/draw.c b/pico/32x/draw.c
new file mode 100644 (file)
index 0000000..794e2d4
--- /dev/null
+++ b/pico/32x/draw.c
@@ -0,0 +1,58 @@
+#include "../pico_int.h"
+
+static void convert_pal555(void)
+{
+  unsigned int *ps = (void *)Pico32xMem->pal;
+  unsigned int *pd = (void *)Pico32xMem->pal_native;
+  unsigned int m1 = 0x001f001f;
+  unsigned int m2 = 0x03e003e0;
+  unsigned int m3 = 0xfc00fc00;
+  int i;
+
+  // place prio to LS green bit
+  for (i = 0x100/2; i > 0; i--, ps++, pd++) {
+    unsigned int t = *ps;
+    *pd = ((t & m1) << 11) | ((t & m2) << 1) | ((t & m3) >> 10);
+  }
+
+  Pico32x.dirty_pal = 0;
+}
+
+void FinalizeLine32xRGB555(int sh, int line)
+{
+  unsigned short *pd = DrawLineDest;
+  unsigned short *pal = Pico32xMem->pal_native;
+  unsigned char *pb = HighCol + 8;
+  unsigned short cram0;
+
+  // this is a bit hackish:
+  // we swap cram color 0 with color that is used for background,
+  // as bg is forced to 0 when we do 32X
+  cram0 = Pico.cram[0];
+  Pico.cram[0] = Pico.cram[Pico.video.reg[7] & 0x3f];
+
+  FinalizeLineRGB555(sh, line);
+  Pico.cram[0] = cram0;
+
+  if ((Pico32x.vdp_regs[0] & 3) == 0)
+    return; // blanking
+
+  if (Pico32x.dirty_pal)
+    convert_pal555();
+
+  if ((Pico32x.vdp_regs[0] & P32XV_Mx) == 1) {
+    unsigned short *dram = (void *)Pico32xMem->dram[Pico32x.vdp_regs[0x0a/2] & P32XV_FS];
+    unsigned short *ps = dram + dram[line];
+    unsigned short t;
+    int i;
+    for (i = 320/2; i > 0; i--, ps++, pd += 2, pb += 2) {
+      t = pal[*ps >> 8];
+      if (pb[0] == 0 || (t & 0x20))
+        pd[0] = t;
+      t = pal[*ps & 0xff];
+      if (pb[1] == 0 || (t & 0x20))
+        pd[1] = t;
+    }
+  }
+}
+