From 90b7a7090249c02806a329531e3cca635d962903 Mon Sep 17 00:00:00 2001
From: Tormod Volden <debian.tormod@gmail.com>
Date: Sun, 6 Nov 2016 00:32:15 +0100
Subject: [PATCH] dragon-nx32: Also use internal upper 32K if available

This comes with a small size and speed penalty, maybe we should
make it a compile option.

Signed-off-by: Tormod Volden <debian.tormod@gmail.com>
---
 Kernel/platform-dragon-nx32/discard.c  | 11 ++++-
 Kernel/platform-dragon-nx32/main.c     |  1 +
 Kernel/platform-dragon-nx32/mem-nx32.s | 56 +++++++++++++++++++++++++-
 3 files changed, 65 insertions(+), 3 deletions(-)

diff --git a/Kernel/platform-dragon-nx32/discard.c b/Kernel/platform-dragon-nx32/discard.c
index 83863c5b..ccb12cec 100644
--- a/Kernel/platform-dragon-nx32/discard.c
+++ b/Kernel/platform-dragon-nx32/discard.c
@@ -11,11 +11,20 @@
  * with the last page repeated to fill any holes.
  */
 
+extern uint8_t internal32k;
+
 void pagemap_init(void)
 {
 	int i;
+	int extbanks = membanks;
+
+	/* map upper 32K on Dragon 64/200/Tano */
+	if (!internal32k) {
+		pagemap_add(128);
+		extbanks--;
+	}
 	/* map bank 1 last for init, leave 0 for kernel */
-	for (i = membanks - 1; i > 0; i--)
+	for (i = extbanks - 1; i > 0; i--)
 		pagemap_add(i);
 
 #ifdef SWAPDEV
diff --git a/Kernel/platform-dragon-nx32/main.c b/Kernel/platform-dragon-nx32/main.c
index b351c18d..32f4f481 100644
--- a/Kernel/platform-dragon-nx32/main.c
+++ b/Kernel/platform-dragon-nx32/main.c
@@ -7,6 +7,7 @@
 #include <carts.h>
 
 uint8_t membanks;
+uint8_t internal32k;
 uint8_t system_id;
 uint8_t cartslots = 1;
 uint8_t carttype[4];
diff --git a/Kernel/platform-dragon-nx32/mem-nx32.s b/Kernel/platform-dragon-nx32/mem-nx32.s
index 73ee7a4a..a70c8538 100644
--- a/Kernel/platform-dragon-nx32/mem-nx32.s
+++ b/Kernel/platform-dragon-nx32/mem-nx32.s
@@ -20,9 +20,12 @@
 	.globl _ramsize
 	.globl _procmem
 	.globl _membanks
+	.globl _internal32k
 
 banksel	equ 0xFFBF
 bankoff	equ 0xFFBE
+sammap1	equ 0xFFDF
+sammap0	equ 0xFFDE
 
 	include "kernel.def"
 	include "../kernel09.def"
@@ -38,6 +41,9 @@ zbank	sta banksel	; clear test byte on all possible banks
 	inca
 	cmpa #16
 	blo zbank
+	sta sammap1	; internal 64K
+	clr ,x
+	sta sammap0
 	clra		; now test writing to banks
 	ldb #0xA5
 size_next
@@ -52,8 +58,19 @@ size_next
 	bne size_next
 size_nonram
 	clr banksel	; leave bank 0 selected and kdata mapped in
+	sta sammap1	; check for internal 64K
+	cmpb ,x		; already same value?
+	bne notsame
+	incb		; use another value
+notsame stb ,x
+	cmpb ,x
+	bne int32k
+	clrb
+	inca		; add count for internal upper 32K
+int32k	sta sammap0
+	stb _internal32k
 	sta _membanks
-	inca		; add the internal 32K to the count
+	inca		; add the internal lower 32K to the count
 	ldb #32
 	mul
 	std _ramsize
@@ -68,6 +85,7 @@ map_kernel
 	lda #0	
 	sta map_copy
 	sta banksel
+	sta sammap0
 	puls a,pc
 
 map_process
@@ -75,16 +93,24 @@ map_process
 	beq map_kernel
 map_process_a
 	sta map_copy
+	bmi map1	; map 128 is for the internal upper 32K
+	sta sammap0
 	sta banksel
 	rts
+map1	sta sammap1
+	rts
 
 map_process_always
 	pshs a
 	lda U_DATA__U_PAGE+1		; LSB of 16-bit page
 map_set_a
 	sta map_copy
+	bmi map1a
+	sta sammap0
 	sta banksel
 	puls a,pc
+map1a	sta sammap1
+	puls a,pc
 	
 map_save
 	pshs a
@@ -104,6 +130,10 @@ copybank
 	lda #0xff
 	tfr a,dp
 	puls a
+	tsta
+	bmi copymap1b	; from SAM map 1 to bank B
+	tstb
+	bmi copyamap1	; from bank A to SAM map 1
 	stu cmpend+1	; self-modiying code FTW
 copyf	sta <banksel
 	ldu ,x
@@ -111,9 +141,31 @@ copyf	sta <banksel
 	stu ,x++
 cmpend	cmpx #0
 	blo copyf
-	stb map_copy
+copyret	stb map_copy
 	puls dp,pc
 
+copymap1b
+	stu cmpendb+1
+	stb <banksel
+copyfb	sta <sammap1
+	ldu ,x
+	sta <sammap0
+	stu ,x++
+cmpendb cmpx #0
+	blo copyfb
+	bra copyret
+
+copyamap1
+	stu cmpenda+1
+	sta <banksel
+copyfa	sta <sammap0
+	ldu ,x
+	sta <sammap1
+	stu ,x++
+cmpenda cmpx #0
+	blo copyfa
+	bra copyret
+
 map_store	.db 0
 map_copy	.db 0
 
-- 
2.34.1