X-Git-Url: http://git.joshuawise.com/fpgaboy.git/blobdiff_plain/c87db60a8f262ec834a46432e5d7b9a4faf09e09..616eebe0bdb3166e9cfda312d6425910b2addf8f:/rom.asm

diff --git a/rom.asm b/rom.asm
new file mode 100644
index 0000000..2ede41c
--- /dev/null
+++ b/rom.asm
@@ -0,0 +1,139 @@
+	SECTION "a",HOME
+main:
+	ld c, $51
+	ld a, $FF
+	ld [c],a
+	ld sp,$DFFF
+
+	ld hl,text
+	call puts
+	
+	call memtest
+	call waitsw
+	jp main
+
+text:
+	db $1B,"[1mFPGABoy Diagnostic ROM",$1B,"[0m",$0D,$0A,0
+
+memtest:
+	ld hl,memteststr
+	call puts
+	
+	ld hl, $C000
+.wr:
+	ld a,h
+	xor l
+	ld [hli],a
+	ld a, $DF
+	cp h
+	jp nz, .wr
+	ld a, $80
+	cp l
+	jp nz, .wr
+
+	ld hl, $C000
+.rd:
+	ld a,h
+	xor l
+	ld b,a
+	ld a, [hli]
+	cp b
+	jp nz, .memfail
+	
+	ld a, $DF
+	cp h
+	jp nz, .rd
+	ld a, $80
+	cp l
+	jp nz, .rd
+	
+	ld hl, testokstr
+	call puts
+	ret
+.memfail:
+	@ decrement hl the easy way
+	ld a,[hld]
+	push hl
+	ld hl, failatstr
+	call puts
+	pop hl
+	ld a, h
+	call puthex
+	ld a, l
+	call puthex
+	ld a, $0A
+	call putc
+	ld a, $0D
+	call putc
+	ret
+
+memteststr:
+	db "Testing memory from $C000 to $DF80...",0
+testokstr:
+	db " OK!",$0D,$0A,0
+failatstr:
+	db " Test failed at $",0
+puthex:
+	push af
+	rra
+	rra
+	rra
+	rra
+	ld b,$0F
+	and b
+	ld b,$30
+	add b
+	call putc
+	pop af
+	ld b,$0F
+	and b
+	ld b,$30
+	add b
+	call putc
+	ret
+
+waitsw:
+	ld hl,waitswstr
+	call puts
+	
+	ld c, $51
+	ld a, $00
+	ld [c],a
+	
+	ld c, $51
+	ld b, $0
+.loop1:
+	ld a,[c]
+	cp b
+	jp z,.loop1
+.loop2:
+	ld a,[c]
+	cp b
+	jp nz,.loop2
+	ret
+
+waitswstr:
+	db "Diagnostic ROM complete; flip switches to nonzero and then to zero to reset.",$0D,$0A,0
+
+putc:
+	push af
+	ld b, 0
+	ld c, $50
+.waitport:
+	ld a,[c]
+	cp b
+	jp nz,.waitport
+	pop af
+	ld [c],a
+	ret
+
+puts:
+	ld a, [hli]
+	ld b, $00
+	cp b
+	jp z, .done
+	call putc
+	jp puts
+.done:
+	ret
+