X-Git-Url: http://git.joshuawise.com/fpgaboy.git/blobdiff_plain/dadf7990cbca24581bbb3c036df717dd59bdea41..06ad3a30038ac8ca45dd7b0c34213c0c8335c17c:/rom.asm

diff --git a/rom.asm b/rom.asm
index 2e98e13..93f8524 100644
--- a/rom.asm
+++ b/rom.asm
@@ -104,13 +104,20 @@ waitsw:
 	ld hl,waitswstr
 	call puts
 	
+	ld c, $07
+	ld a, $07	;start timer, 4.096KHz
+	ld [c], a
+	
 	ld c, $51
 	ld a, $00
 	ld [c],a
 	
+.loop1:
+	push bc
+	call testa
+	pop bc
 	ld c, $51
 	ld b, $0
-.loop1:
 	ld a,[c]
 	cp b
 	jr z,.loop1
@@ -121,7 +128,24 @@ waitsw:
 	ret
 
 waitswstr:
-	db "Diagnostic ROM complete; flip switches to nonzero and then to zero to reset.",$0D,$0A,0
+	db "Diagnostic ROM complete; flip switches to nonzero and then to zero to reset. Expect A.",$0D,$0A,0
+
+testa:
+	ld c, $0F
+	ld a, [c]
+	ld b, $00
+	cp b
+	ret z
+	xor a
+	ld [c], a
+	ld hl, $D000
+	ld c, [hl]
+	inc bc
+	ld [hl], c
+	ld a, c
+	ld c, $50
+	ld [c], a
+	ret
 
 ; Core instruction basic acceptance tests.
 insntest:
@@ -232,14 +256,12 @@ insntest:
 
 ; Serial port manipulation functions.
 putc:
-	push af
 	ld b, 0
 	ld c, $50
 .waitport:
 	ld a,[c]
 	cp b
 	jr nz,.waitport
-	pop af
 	ld [c],a
 	ret