+ // Assume incoming GP0 command is 0xE1..0xE6, convert to 1..6
+ u8 num = (cmd_word >> 24) & 7;
+ gpu.ex_regs[num] = cmd_word; // Update gpulib register
+ switch (num) {
+ case 1: {
+ // GP0(E1h) - Draw Mode setting (aka "Texpage")
+ u32 cur_texpage = gpu_unai.GPU_GP1 & 0x7FF;
+ u32 new_texpage = cmd_word & 0x7FF;
+ if (cur_texpage != new_texpage) {
+ gpu_unai.GPU_GP1 = (gpu_unai.GPU_GP1 & ~0x7FF) | new_texpage;
+ gpuSetTexture(gpu_unai.GPU_GP1);
+ }
+ } break;
+
+ case 2: {
+ // GP0(E2h) - Texture Window setting
+ if (cmd_word != gpu_unai.TextureWindowCur) {
+ static const u8 TextureMask[32] = {
+ 255, 7, 15, 7, 31, 7, 15, 7, 63, 7, 15, 7, 31, 7, 15, 7,
+ 127, 7, 15, 7, 31, 7, 15, 7, 63, 7, 15, 7, 31, 7, 15, 7
+ };
+ gpu_unai.TextureWindowCur = cmd_word;
+ gpu_unai.TextureWindow[0] = ((cmd_word >> 10) & 0x1F) << 3;
+ gpu_unai.TextureWindow[1] = ((cmd_word >> 15) & 0x1F) << 3;
+ gpu_unai.TextureWindow[2] = TextureMask[(cmd_word >> 0) & 0x1F];
+ gpu_unai.TextureWindow[3] = TextureMask[(cmd_word >> 5) & 0x1F];
+ gpu_unai.TextureWindow[0] &= ~gpu_unai.TextureWindow[2];
+ gpu_unai.TextureWindow[1] &= ~gpu_unai.TextureWindow[3];
+
+ // Inner loop vars must be updated whenever texture window is changed:
+ const u32 fb = FIXED_BITS; // # of fractional fixed-pt bits of u4/v4
+ gpu_unai.u_msk = (((u32)gpu_unai.TextureWindow[2]) << fb) | ((1 << fb) - 1);
+ gpu_unai.v_msk = (((u32)gpu_unai.TextureWindow[3]) << fb) | ((1 << fb) - 1);
+
+ gpuSetTexture(gpu_unai.GPU_GP1);
+ }
+ } break;
+
+ case 3: {
+ // GP0(E3h) - Set Drawing Area top left (X1,Y1)
+ gpu_unai.DrawingArea[0] = cmd_word & 0x3FF;
+ gpu_unai.DrawingArea[1] = (cmd_word >> 10) & 0x3FF;
+ } break;
+
+ case 4: {
+ // GP0(E4h) - Set Drawing Area bottom right (X2,Y2)
+ gpu_unai.DrawingArea[2] = (cmd_word & 0x3FF) + 1;
+ gpu_unai.DrawingArea[3] = ((cmd_word >> 10) & 0x3FF) + 1;
+ } break;
+
+ case 5: {
+ // GP0(E5h) - Set Drawing Offset (X,Y)
+ gpu_unai.DrawingOffset[0] = ((s32)cmd_word<<(32-11))>>(32-11);
+ gpu_unai.DrawingOffset[1] = ((s32)cmd_word<<(32-22))>>(32-11);
+ } break;
+
+ case 6: {
+ // GP0(E6h) - Mask Bit Setting
+ gpu_unai.Masking = (cmd_word & 0x2) << 1;
+ gpu_unai.PixelMSB = (cmd_word & 0x1) << 8;
+ } break;
+ }
+}
+#endif