From 3e759e4d21e42f9eb830926f4e820d33e5cfa91e Mon Sep 17 00:00:00 2001
From: flowenol <flovenol@gmail.com>
Date: Sun, 15 Jan 2023 02:40:58 +0100
Subject: [PATCH] Added support for alternative memory locations of Apple-1
 Serial Interface Card

---
 apple1cartridge.cfg |  2 +-
 apple1serial.s      | 80 +++++++++++++++++++++++++++++++++++----------
 2 files changed, 64 insertions(+), 18 deletions(-)

diff --git a/apple1cartridge.cfg b/apple1cartridge.cfg
index 109313b..c1ffc58 100644
--- a/apple1cartridge.cfg
+++ b/apple1cartridge.cfg
@@ -1,5 +1,5 @@
 MEMORY {
-	BASROM:		start = $6000, size = $2000, fill = yes, file = %O;
+	BASROM:		start = $6000, size = $200A, fill = yes, file = %O;
 }
 
 SEGMENTS {
diff --git a/apple1serial.s b/apple1serial.s
index 1b48e05..56adee3 100644
--- a/apple1serial.s
+++ b/apple1serial.s
@@ -7,11 +7,20 @@
 .import ERROR, FIX_LINKS, OUTDO
 .export SerialLoad, SerialSave, SerialMenu
 
-SERIAL_MONITOR := $C100
-SERIAL_READY := $C000
-SERIAL_ID := $C0FC
-SERIAL_API_READ := $C1EC
-SERIAL_API_WRITE := $C213
+SERIAL_MONITOR_C000 := $C100
+SERIAL_READY_C000 := $C000
+SERIAL_ID_C000 := $C0FC
+SERIAL_API_READ_C000 := $C1EC
+SERIAL_API_WRITE_C000 := $C213
+
+SERIAL_MONITOR_C300 := $C400
+SERIAL_READY_C300 := $C300
+SERIAL_ID_C300 := $C3FC
+SERIAL_API_READ_C300 := $C4EC
+SERIAL_API_WRITE_C300 := $C513
+
+; 0 - $C000, 1 - $C300
+SERIAL_VARIANT := $40
 
 ; ZP locations get backed up here
 ZPTemp		:= $0380
@@ -34,18 +43,37 @@ STR2INT_END := $0A
 ; See if Apple-1 Serial Interface card is present and display error if not
 ; ----------------------------------------------------------------------------
 CheckSerial:
-	ldy	SERIAL_ID
+	ldy	SERIAL_ID_C000
+	cpy	#'A'
+	bne	@1
+	ldy	SERIAL_ID_C000 + 1
+	cpy	#'1'
+	bne	@1
+	ldy	SERIAL_ID_C000 + 2
+	cpy	#'S'
+	bne	@1
+	ldy	SERIAL_ID_C000 + 3
+	cpy	#'I'
+	bne	@1
+	lda #$00
+	sta SERIAL_VARIANT
+	rts
+
+@1:
+	ldy	SERIAL_ID_C300
 	cpy	#'A'
 	bne	SerialErr
-	ldy	SERIAL_ID + 1
+	ldy	SERIAL_ID_C300 + 1
 	cpy	#'1'
 	bne	SerialErr
-	ldy	SERIAL_ID + 2
+	ldy	SERIAL_ID_C300 + 2
 	cpy	#'S'
 	bne	SerialErr
-	ldy	SERIAL_ID + 3
+	ldy	SERIAL_ID_C300 + 3
 	cpy	#'I'
 	bne	SerialErr
+	lda #$01
+	sta SERIAL_VARIANT
 	rts
 
 SerialErr:
@@ -61,8 +89,13 @@ SynErr:
 ; ----------------------------------------------------------------------------
 SerialMenu:
   jsr	CheckSerial
-	jsr SERIAL_MONITOR
-
+	lda SERIAL_VARIANT
+	bne SerialMenuAlt
+	jsr SERIAL_MONITOR_C000
+	rts
+SerialMenuAlt:
+	jsr SERIAL_MONITOR_C300
+	rts
 
 ; ----------------------------------------------------------------------------
 ; Save program via the Apple-1 Serial Interface
@@ -87,10 +120,15 @@ SerialSave:
 	lda	TXTTAB+1
 	sta BEG_ADDR_H
 
-	jsr SERIAL_API_WRITE
+	lda SERIAL_VARIANT
+	bne @2
+	jsr SERIAL_API_WRITE_C000
+	jmp @3
+@2:
+	jsr SERIAL_API_WRITE_C300
+@3:
 	jsr	RestoreZPForSave	; Put the zero page back
   rts
-
 ; ----------------------------------------------------------------------------
 ; Restores the 4 bytes of the ZP which were saved during SerialSave
 ; ----------------------------------------------------------------------------
@@ -137,15 +175,17 @@ GetLength:	; Get file name from input line
 
 @2:
 	cpy	#0			; Read 6 chars or EOL, did we get anything?
-	beq	SynErr
+  bne @3
+	jmp	SynErr
 
+@3:
 	lda #STR2INT_END    ; append integer string end marker
 	sta STR2INT_BUF,y
 	jsr String2Int
 	lda STR2INT_INT
-	bne @3
+	bne @4
 	dec STR2INT_INT+1
-@3:
+@4:
 	dec STR2INT_INT
 	clc
 SetLoadAddresses:
@@ -164,7 +204,13 @@ SetLoadAddresses:
 	lda	TXTTAB+1
 	sta BEG_ADDR_H
 
-	jsr SERIAL_API_READ
+	lda SERIAL_VARIANT
+	bne @1
+	jsr SERIAL_API_READ_C000
+	jmp @2
+@1:
+	jsr SERIAL_API_READ_C300
+@2:
 	jsr	RestoreZPForLoad	; Put the zero page back
 
 	jmp	FIX_LINKS