From: Alan Cox <alan@linux.intel.com>
Date: Fri, 17 Aug 2018 23:51:14 +0000 (+0100)
Subject: sam: restructure loading a bit fix some display and other bugs
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=0c738bf5bd1d7cc85a64e86b3417cd7de207cb8d;p=FUZIX.git

sam: restructure loading a bit fix some display and other bugs

We now get to the point we start trying to boot, and blow up after the
RAM sizing message. I suspect this is program_vectors exploding.
---

diff --git a/Kernel/platform-sam/crt0.s b/Kernel/platform-sam/crt0.s
index e7f0cf53..cb3bca05 100644
--- a/Kernel/platform-sam/crt0.s
+++ b/Kernel/platform-sam/crt0.s
@@ -47,21 +47,12 @@
 ;	Our low bank is set, our high bank is still setup
 ;
 start:
-		; Map the kernel high bank
-		ld a,#4
+		; Map the kernel high bank (2/3)
+		ld a,#2
 		out (251),a
 l1:		jp l1
 		ld sp, #kstack_top
-		; move the common memory where it belongs    
-		ld hl, #s__DATA
-		ld de, #s__COMMONMEM
-		ld bc, #l__COMMONMEM
-		ldir
-		; then the discard
-		ld de, #s__DISCARD
-		ld bc, #l__DISCARD
-		ldir
-		; then zero the data area
+		; Zero the data area (shouldn't be needed)
 		ld hl, #s__DATA
 		ld de, #s__DATA + 1
 		ld bc, #l__DATA - 1
diff --git a/Kernel/platform-sam/sam.s b/Kernel/platform-sam/sam.s
index b437f21e..b6b959e4 100644
--- a/Kernel/platform-sam/sam.s
+++ b/Kernel/platform-sam/sam.s
@@ -36,15 +36,18 @@
             .globl outcharhex
 	    .globl _keyin
 
+	    .globl _vtwipe
+	    .globl _vtinit
+
 	    .globl s__COMMONMEM
 	    .globl l__COMMONMEM
 
             .include "kernel.def"
             .include "../kernel.def"
 
-KERNEL_HIGH	.equ	0
-KERNEL_LOW	.equ	2		; 0/1 high 2/3 low
-VIDEO_LOW	.equ	4
+KERNEL_LOW	.equ	0		; 0/1 low 2/3 high
+KERNEL_HIGH	.equ	2
+VIDEO_LOW	.equ	4		; 4/5 video and font
 
 ; -----------------------------------------------------------------------------
 ;
@@ -71,8 +74,8 @@ _platform_reboot:
 	    .byte 0x00		; Black
 	    .byte 0x40		; Green
 	    .byte 0x20		; Red
-	    .byte 0x70		; White
 clutmap:
+	    .byte 0x70		; White
 
 init_early:
 	    ld a, #0x44		; Kernel is in 0/1 2/3, so video goes above it
@@ -80,9 +83,7 @@ init_early:
 	    out (252), a
 	    ld a, #0x10		; black border, mic 1
 	    out (254), a
-	    in a, (251)
-	    and #0x9F		; low palette colours
-	    ld hl, #clutmap
+	    ld hl, #clutmap	; set low palette colours
 	    ld bc, #4*256 + 248	; 4 colours, port 248
 	    otdr
             ret
@@ -94,16 +95,13 @@ init_hardware:
             ld hl, #(256-64)		; 64K for kernel
             ld (_procmem), hl
 
-            ; set up interrupt vectors for the kernel (also sets up common memory in page 0x000F which is unused)
-            ld hl, #0
-            push hl
-            call _program_vectors
-            pop hl
-
             im 1 ; set CPU interrupt mode
 
 	    ; interrupt mask
-	    ; 60Hz timer on
+	    ; 50Hz timer on
+
+	    call _vtwipe
+	    call _vtinit
 
             ret
 
diff --git a/Kernel/platform-sam/sam_vt.s b/Kernel/platform-sam/sam_vt.s
index 8a9e10af..e1292124 100644
--- a/Kernel/platform-sam/sam_vt.s
+++ b/Kernel/platform-sam/sam_vt.s
@@ -28,11 +28,13 @@
 	.globl _vtattr_notify
 	.globl _vtattr_cap
 
+	.globl _vtwipe
+
 	.globl map_video
 	.globl unmap_video
 	.globl ___hard_di
 
-_fontdata_8x8_exp2	.equ	0xE000	; in video bank
+_fontdata_8x8_exp2	.equ	0x6000	; in video bank
 
 VIDEO_PAGE	.equ	4
 
@@ -43,8 +45,11 @@ base_addr:
 	ld a,d		; save X
 	ld d,e		; 256 * Y
 	ld e,#0
-	srl d
-	srl e		; this is DE = E * 128
+	sla e
+	sla d		; this is DE = E * 512
+	sla e
+	sla d		; this is DE = E * 1024
+
 	; A is a char 0-63 - need a byte 0-126
 	; Aligned so no carry issues
 	add a
@@ -103,9 +108,8 @@ _plot_char:
 	ld bc,#_fontdata_8x8_exp2	; plus font base
 	add hl,bc
 	call map_video
-	ld b,#20		; it gets decremented by 4 by the ldi's
-				; and once by djnz, and we need to do it
-				; four times
+	ld bc,#0x04FF		; it gets decremented by DJNZ while the FF
+				; ensures the ldi never decrements B
 plot_loop:
 	ldi			; copy expanded char
 	ldi
@@ -177,6 +181,15 @@ wipe_rowpair:
 	jr nz, wipe_line
 	jp pop_unmap
 
+_vtwipe:
+	call map_video
+	ld hl,#0
+	ld de,#1
+	ld bc,#24575
+	ld (hl),#0
+	ldir
+	call unmap_video
+	ret
 ;
 ;	TODO
 ;