From 842a79ae5d910f0192bfd1524310039b62769698 Mon Sep 17 00:00:00 2001
From: b1ackmai1er <difficultylevelhigh@gmail.com>
Date: Sun, 24 Mar 2024 15:36:32 +0800
Subject: [PATCH] Correct the logical sequence of the Duo Dual UART ports

Make the first UART port detected be Channel A $78-$7F : CHSEL=1. ( logic 0 on the CHSEL selects the UART channel B while a logic 1 selects UART channel A. )
---
 Source/HBIOS/uart.asm | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/Source/HBIOS/uart.asm b/Source/HBIOS/uart.asm
index f0126ead..c33341d8 100644
--- a/Source/HBIOS/uart.asm
+++ b/Source/HBIOS/uart.asm
@@ -1163,6 +1163,13 @@ UART_CFG_MFP:
 	; DUAL UART CHANNEL A
 	.DB	0				; DEVICE NUMBER (UPDATED DURING INIT)
 	.DB	0				; UART TYPE
+	.DB	UARTDBASE+8			; IO PORT BASE (RBR, THR)
+	.DB	UARTDBASE+8 + UART_LSR		; LINE STATUS PORT (LSR)
+	.DW	UARTCFG				; LINE CONFIGURATION
+	.DW	0				; SHOULD NEVER NEED INT HANDLER
+	; DUAL UART CHANNEL B
+	.DB	0				; DEVICE NUMBER (UPDATED DURING INIT)
+	.DB	0				; UART TYPE
 	.DB	UARTDBASE			; IO PORT BASE (RBR, THR)
 	.DB	UARTDBASE + UART_LSR		; LINE STATUS PORT (LSR)
 	.DW	UARTCFG				; LINE CONFIGURATION
@@ -1171,14 +1178,6 @@ UART_CFG_MFP:
 	.ECHO	"UART: MODE=DUAL, IO="
 	.ECHO	UARTDBASE+0
 	.ECHO	"\n"
-;
-	; DUAL UART CHANNEL B
-	.DB	0				; DEVICE NUMBER (UPDATED DURING INIT)
-	.DB	0				; UART TYPE
-	.DB	UARTDBASE+8			; IO PORT BASE (RBR, THR)
-	.DB	UARTDBASE+8 + UART_LSR		; LINE STATUS PORT (LSR)
-	.DW	UARTCFG				; LINE CONFIGURATION
-	.DW	0				; SHOULD NEVER NEED INT HANDLER
 ;
 	.ECHO	"UART: MODE=DUAL, IO="
 	.ECHO	UARTDBASE+8