fix vdu variable numbering

when the `Context::readVariable` call is made, the variable number will already be within the appropriate feature flag range - this fixes that
AgonConsole8 · Feb 6, 2025 · fb795a0 · fb795a0
1 parent 254ceff
commit fb795a0
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Showing 2 changed files with 13 additions and 10 deletions.
diff --git a/video/agon.h b/video/agon.h
@@ -413,8 +413,11 @@
 #define FEATUREFLAG_VDU_VARIABLES_START	0x1000	// VDU variables start at 0x1000
 #define FEATUREFLAG_VDU_VARIABLES_END	0x1FFF	// VDU variables end
 #define FEATUREFLAG_VDU_VARIABLES_MASK	0x0FFF	// VDU variables mask
-#define FEATUREFLAG_VDU_VAR_PALETTE		0x1200	// Palette variables start (block of 64)
-#define FEATUREFLAG_VDU_VAR_PALETTE_END	0x123F	// Palette variables end
+
+#define VDU_VAR_PALETTE			0x200	// Palette variables start (block of 64)
+#define VDU_VAR_PALETTE_END		0x23F	// Palette variables end
+#define VDU_VAR_CHARMAPPING		0x300	// Character to bitmap mapping start (block of 256)
+#define VDU_VAR_CHARMAPPING_END	0x3FF	// Character to bitmap mapping end
 
 #define LOGICAL_SCRW			1280	// As per the BBC Micro standard
 #define LOGICAL_SCRH			1024

diff --git a/video/context.h b/video/context.h
@@ -372,14 +372,14 @@ class Context {
 }
 
 bool Context::readVariable(uint16_t var, uint16_t * value) {
-	if (var >= FEATUREFLAG_VDU_VAR_PALETTE && var <= FEATUREFLAG_VDU_VAR_PALETTE_END) {
+	if (var >= VDU_VAR_PALETTE && var <= VDU_VAR_PALETTE_END) {
 		if (value) {
-			*value = palette[(var - FEATUREFLAG_VDU_VAR_PALETTE) & (getVGAColourDepth() - 1)];
+			*value = palette[(var - VDU_VAR_PALETTE) & (getVGAColourDepth() - 1)];
 		}
 		return true;
 	}
-	if (var >= FEATUREFLAG_VDU_VAR_CHARMAPPING && var <= FEATUREFLAG_VDU_VAR_CHARMAPPING_END) {
-		auto c = var - FEATUREFLAG_VDU_VAR_CHARMAPPING;
+	if (var >= VDU_VAR_CHARMAPPING && var <= VDU_VAR_CHARMAPPING_END) {
+		auto c = var - VDU_VAR_CHARMAPPING;
 		if (charToBitmap[c] != 65535) {
 			if (value) {
 				*value = charToBitmap[c];
@@ -766,15 +766,15 @@ bool Context::readVariable(uint16_t var, uint16_t * value) {
 }
 
 void Context::setVariable(uint16_t var, uint16_t value) {
-	if (var >= FEATUREFLAG_VDU_VAR_PALETTE && var <= FEATUREFLAG_VDU_VAR_PALETTE_END) {
+	if (var >= VDU_VAR_PALETTE && var <= VDU_VAR_PALETTE_END) {
 		if (value >= 64) {
 			return;
 		}
-		setLogicalPalette(var - FEATUREFLAG_VDU_VAR_PALETTE, value, 0, 0, 0);
+		setLogicalPalette(var - VDU_VAR_PALETTE, value, 0, 0, 0);
 		return;
 	}
-	if (var >= FEATUREFLAG_VDU_VAR_CHARMAPPING && var <= FEATUREFLAG_VDU_VAR_CHARMAPPING_END) {
-		mapCharToBitmap(var - FEATUREFLAG_VDU_VAR_CHARMAPPING, value);
+	if (var >= VDU_VAR_CHARMAPPING && var <= VDU_VAR_CHARMAPPING_END) {
+		mapCharToBitmap(var - VDU_VAR_CHARMAPPING, value);
 		return;
 	}
 	switch (var) {