Rework of the scan-doubling, pixel-doubling, and aspect ratio calculation logic

johnnovak · johnnovak · commit be7922703d04 · 2023-06-29T13:41:06.000+10:00
TODO details
diff --git a/include/vga.h b/include/vga.h
@@ -881,7 +881,6 @@ void VGA_LogInitialization(const char *adapter_name,
                            const size_t num_modes);
 
 void VGA_SetVgaDoubleScanHandling(const VgaDoubleScanHandling vga_double_scane_handling);
-bool VGA_IsDoubleScanningVgaModes();
 
 extern VGA_Type vga;
 
diff --git a/src/hardware/vga.cpp b/src/hardware/vga.cpp
@@ -306,20 +306,6 @@ double VGA_GetPreferredRate()
 	return vga.draw.dos_refresh_hz;
 }
 
-// Are we using a VGA card and asked to emulate double-scanning? (This is a
-// helper function to avoid repeating this logic in the VGA drawing and CRTC
-// areas).
-bool VGA_IsDoubleScanningVgaModes()
-{
-	return IS_VGA_ARCH &&
-	       vga.draw.vga_double_scan_handling == VgaDoubleScanHandling::DoubleScan &&
-	       (vga.mode == M_EGA || vga.mode == M_VGA);
-
-	// TODO: Non-composite CGA modes should be included here too, as VGA
-	// cards also line-doubled those modes, however more work is needed to
-	// correctly draw double-scanned CGA lines.
-}
-
 void VGA_SetClock(const Bitu which, const uint32_t desired_clock)
 {
 	if (svga.set_clock) {
@@ -522,3 +508,4 @@ void SVGA_Setup_Driver(void) {
 		break;
 	}
 }
+
diff --git a/src/hardware/vga_crtc.cpp b/src/hardware/vga_crtc.cpp
@@ -146,12 +146,6 @@ void vga_write_p3d5(io_port_t, io_val_t value, io_width_t)
 			vga.config.line_compare = (vga.config.line_compare & 0x5ff) |
 			                          (val & 0x40) << 3;
 		}
-		if (VGA_IsDoubleScanningVgaModes()) {
-			vga.draw.address_line_total = (val & 0x1F) + 1;
-			if (val & 0x80) {
-				vga.draw.address_line_total *= 2;
-			}
-		}
 		vga.crtc.maximum_scan_line.data = val;
 		VGA_StartResize();
 		break;
diff --git a/src/hardware/vga_draw.cpp b/src/hardware/vga_draw.cpp

Original file line number	Diff line number	Diff line change
`@@ -306,20 +306,6 @@ double VGA_GetPreferredRate()`
`306`	`306`	`return vga.draw.dos_refresh_hz;`
`307`	`307`	`}`
`308`	`308`
`309`		`-// Are we using a VGA card and asked to emulate double-scanning? (This is a`
`310`		`-// helper function to avoid repeating this logic in the VGA drawing and CRTC`
`311`		`-// areas).`
`312`		`-bool VGA_IsDoubleScanningVgaModes()`
`313`		`-{`
`314`		`- return IS_VGA_ARCH &&`
`315`		`- vga.draw.vga_double_scan_handling == VgaDoubleScanHandling::DoubleScan &&`
`316`		`- (vga.mode == M_EGA \|\| vga.mode == M_VGA);`
`317`		`-`
`318`		`- // TODO: Non-composite CGA modes should be included here too, as VGA`
`319`		`- // cards also line-doubled those modes, however more work is needed to`
`320`		`- // correctly draw double-scanned CGA lines.`
`321`		`-}`
`322`		`-`
`323`	`309`	`void VGA_SetClock(const Bitu which, const uint32_t desired_clock)`
`324`	`310`	`{`
`325`	`311`	`if (svga.set_clock) {`
`@@ -522,3 +508,4 @@ void SVGA_Setup_Driver(void) {`
`522`	`508`	`break;`
`523`	`509`	`}`
`524`	`510`	`}`
	`511`	`+`