From: Alan Cox <alan@linux.intel.com>
Date: Fri, 17 Aug 2018 22:23:46 +0000 (+0100)
Subject: sam: Get to the point we enter the kernel
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=36438e23f567f9470d6d1c8479da99469a806f57;p=FUZIX.git

sam: Get to the point we enter the kernel

Fix for binman to allow for our page below code
Assorted logic fixes to the boot and setup code
Make crt0 map the high kernel bank

Video is still broken and we die early in setup but we made it into C
---

diff --git a/Kernel/platform-sam/Makefile b/Kernel/platform-sam/Makefile
index e09d60f3..d077d334 100644
--- a/Kernel/platform-sam/Makefile
+++ b/Kernel/platform-sam/Makefile
@@ -45,10 +45,12 @@ image:	boot setup
 	dd if=/dev/zero of=fuzix.raw bs=512 count=1600
 	# Boot block at track 4 sector 1
 	dd if=boot.bin of=fuzix.raw bs=512 seek=40 count=1 conv=notrunc
-	# Kernel from track 4 sector 2
-	dd if=../fuzix.bin of=fuzix.raw bs=512 seek=41 conv=notrunc
+	# Kernel from track 4 sector 2 highest 32K first
+	dd if=../fuzix.bin of=fuzix.raw bs=512 seek=41 skip=64 count=64 conv=notrunc
+	# Low 32K next
+	dd if=../fuzix.bin of=fuzix.raw bs=512 seek=105 count=64 conv=notrunc
 	# Font and setup from 64K further on
-	dd if=setup.bin of=fuzix.raw bs=512 seek=169 conv=notrunc
+	dd if=setup.bin of=fuzix.raw bs=512 seek=169 skip=64 conv=notrunc
 	# Now shuffle it into a .mgt file
 	../tools/raw2mgt fuzix.raw fuzix.mgt
 
diff --git a/Kernel/platform-sam/boot.s b/Kernel/platform-sam/boot.s
index 02a3e31a..fefb1dc5 100644
--- a/Kernel/platform-sam/boot.s
+++ b/Kernel/platform-sam/boot.s
@@ -43,7 +43,7 @@ boot:
 	jp go
 go:
 	ld sp,#go
-	ld de,#0x0401		; track 4 sector 2 (we are sector 1)
+	ld de,#0x0402		; track 4 sector 2 (we are sector 1)
 	ld a,e			; Start in bank 2
 	ld hl,#0x8000		; Which we map high
 	out (HIMEM),a
@@ -59,7 +59,7 @@ next_sec:
 	ex af,af'
 still_good:
 	ld a,e			; update the sector register
-	ld (SECTOR),a
+	out (SECTOR),a
 dread:	ld a,#CMD_READ		; Ask for data from the FDC
 	out (CMD),a
 	ld b,#20		; Wait for FDC
diff --git a/Kernel/platform-sam/crt0.s b/Kernel/platform-sam/crt0.s
index d0ef9148..e7f0cf53 100644
--- a/Kernel/platform-sam/crt0.s
+++ b/Kernel/platform-sam/crt0.s
@@ -44,8 +44,13 @@
 
 ;
 ;	Once the loader completes it jumps here
+;	Our low bank is set, our high bank is still setup
 ;
 start:
+		; Map the kernel high bank
+		ld a,#4
+		out (251),a
+l1:		jp l1
 		ld sp, #kstack_top
 		; move the common memory where it belongs    
 		ld hl, #s__DATA
diff --git a/Kernel/platform-sam/sam.s b/Kernel/platform-sam/sam.s
index a841e4bd..b437f21e 100644
--- a/Kernel/platform-sam/sam.s
+++ b/Kernel/platform-sam/sam.s
@@ -281,9 +281,8 @@ rst38:	    jp interrupt_high		; Interrupt handling stub
 	    nop
 	    nop
 	    nop
-	    ; 40
-	    .ds 0x26
-nmi_handler:		; FIXME: check ends up at 0066
+	    .ds 0x27
+nmi_handler:		; Should be at 0x66
 	    retn
 
 	    .area _PAGEH
diff --git a/Kernel/platform-sam/setup.lnk b/Kernel/platform-sam/setup.lnk
index ceacb937..c7322d08 100644
--- a/Kernel/platform-sam/setup.lnk
+++ b/Kernel/platform-sam/setup.lnk
@@ -1,5 +1,6 @@
 -m
 -i setup.ihx
+-b _BOOTSTRAP=0x8000
 setup.rel
 ../font8x8_exp2.rel
 -e
diff --git a/Kernel/platform-sam/setup.s b/Kernel/platform-sam/setup.s
index 5825b3a8..bdce0c5a 100644
--- a/Kernel/platform-sam/setup.s
+++ b/Kernel/platform-sam/setup.s
@@ -12,18 +12,26 @@
 	.globl _fontdata_8x8_exp2
 	
 	.area _BOOTSTRAP
+	.area _FONT
+
+	.area _BOOTSTRAP
 
 MODE3	.equ	0x40		; I think ?
+LOMEM	.equ	250
+VIDEO	.equ	252
+BORDER	.equ	254
 
 bootstrap:
 	; Blue border for debugging
 	ld a,#1
-	out (254),a
+	out (BORDER),a
 ;
 ;	The kernel low 32K is currently sitting in 4/5 not 0/1 so
 ;	move it. The upper 32K is already in 2/3
 ;
 	ld de,#0x2420
+	ld sp,#here
+here:
 	call copy16k
 	ld de,#0x2521
 	call copy16k
@@ -33,7 +41,7 @@ bootstrap:
 ;
 	; Map bank 4/5 low
 	ld a,#0x24
-	out (250),a
+	out (LOMEM),a
 	; Put the font data where it belongs
 	ld hl,#_fontdata_8x8_exp2
 	ld de,#0xE000-0x8000
@@ -44,26 +52,26 @@ bootstrap:
 ;
 	; Put the video in the right place and set the mode
 	ld a,#4 + MODE3
-	out (252),a
+	out (VIDEO),a
 	; Map the kernel low
 	ld a,#0x20		; ROM off bank 0/1
-	out (250),a
+	out (LOMEM),a
 	; Black border to hint where we got to
 	xor a
-	out (254),a
+	out (BORDER),a
 	jp 0x100
 ;
 ;	Move 16K via a bounce buffer
 ;
 copy16k:
 	ld a,d			; soure bank
-	out (250),a
+	out (LOMEM),a
 	ld a,e
 	ld hl,#0x0000
 	ld de,#0xC000		; buffer via bank 7
 	ld bc,#0x4000
 	ldir
-	out (250),a		; dest bank
+	out (LOMEM),a		; dest bank
 	ld hl,#0xC000
 	ld de,#0x0000
 	ld bc,#0x4000
diff --git a/Kernel/tools/binman.c b/Kernel/tools/binman.c
index ab54fd53..d8af1563 100644
--- a/Kernel/tools/binman.c
+++ b/Kernel/tools/binman.c
@@ -10,7 +10,7 @@ static unsigned int s__CODE, s__CODE2, s__INITIALIZER, s__DATA,
     s__INITIALIZED, s__INITIALIZER, s__COMMONMEM, s__VIDEO, l__INITIALIZED,
     l__GSFINAL, l__GSINIT, l__COMMONMEM, s__FONT, l__FONT, s__DISCARD,
     l__DISCARD, l__CODE, l__CODE2, l__VIDEO, l__DATA, s__CONST, l__CONST,
-    s__HEAP, l__HEAP;
+    s__HEAP, l__HEAP, s__PAGE0 = 0xFFFF;
 
 
 static void ProcessMap(FILE * fp)
@@ -73,6 +73,8 @@ static void ProcessMap(FILE * fp)
 			sscanf(p1, "%x", &s__HEAP);
 		if (strcmp(p2, "l__HEAP") == 0)
 			sscanf(p1, "%x", &l__HEAP);
+		if (strcmp(p2, "s__PAGE0") == 0)
+			sscanf(p1, "%x", &s__PAGE0);
 	}
 }
 
@@ -152,6 +154,9 @@ int main(int argc, char *argv[])
 
 	/* Our standard layout begins with the code */
 	start = s__CODE;
+	/* But for some cases we have a 0 page we need to keep */
+	if (s__PAGE0 != 0xFFFF)
+		start = 0;
 
 	/* TODO: Support a proper discardable high discard in other mappings */