# HG changeset patch
# User Michael Pavone <pavone@retrodev.com>
# Date 1642579681 28800
# Node ID 27bbfcb7850a4dc0c8f7c90050ce2cc9892b89fb
# Parent  c4d066d798c401659f432a069d4a8790aebcc44c
Fix byte write behavior on a few gate array regs to pass the VAR test in mcd-verificator

diff -r c4d066d798c4 -r 27bbfcb7850a segacd.c
--- a/segacd.c	Tue Jan 18 23:54:02 2022 -0800
+++ b/segacd.c	Wed Jan 19 00:08:01 2022 -0800
@@ -377,10 +377,22 @@
 	segacd_context *cd = m68k->system;
 	uint32_t reg = (address & 0x1FF) >> 1;
 	uint16_t value16;
-	if (address & 1) {
-		value16 = cd->gate_array[reg] & 0xFF00 | value;
-	} else {
-		value16 = cd->gate_array[reg] & 0xFF | (value << 8);
+	switch (address >> 1)
+	{
+	case GA_CDC_HOST_DATA:
+	case GA_CDC_DMA_ADDR:
+	case GA_STOP_WATCH:
+	case GA_COMM_FLAG:
+	case GA_CDD_FADER:
+		//these registers treat all writes as word-wide
+		value16 = value | (value << 8);
+		break;
+	default:
+		if (address & 1) {
+			value16 = cd->gate_array[reg] & 0xFF00 | value;
+		} else {
+			value16 = cd->gate_array[reg] & 0xFF | (value << 8);
+		}
 	}
 	return sub_gate_write16(address, vcontext, value16);
 }
@@ -588,10 +600,19 @@
 	segacd_context *cd = gen->expansion;
 	uint32_t reg = (address & 0x1FF) >> 1;
 	uint16_t value16;
-	if (address & 1) {
-		value16 = cd->gate_array[reg] & 0xFF00 | value;
-	} else {
-		value16 = cd->gate_array[reg] & 0xFF | (value << 8);
+	switch (reg >> 1)
+	{
+	case GA_HINT_VECTOR:
+	case GA_COMM_FLAG:
+		//writes to these regs are always treated as word wide
+		value16 = value | (value << 8);
+		break;
+	default:
+		if (address & 1) {
+			value16 = cd->gate_array[reg] & 0xFF00 | value;
+		} else {
+			value16 = cd->gate_array[reg] & 0xFF | (value << 8);
+		}
 	}
 	return main_gate_write16(address, vcontext, value16);
 }