X-Git-Url: http://git.joshuawise.com/fpgaboy.git/blobdiff_plain/616eebe0bdb3166e9cfda312d6425910b2addf8f..f26748f71f3f39de15a1c07f95c15f8c4481f452:/rom.asm?ds=inline

diff --git a/rom.asm b/rom.asm
index 2ede41c..d650855 100644
--- a/rom.asm
+++ b/rom.asm
@@ -1,57 +1,64 @@
 	SECTION "a",HOME
+
 main:
-	ld c, $51
+	ld c, $51	; Note that we are alive.
 	ld a, $FF
 	ld [c],a
-	ld sp,$DFFF
 
-	ld hl,text
+	ld sp, $DFFF
+
+	ld hl, signon
 	call puts
 	
 	call memtest
+
+	call insntest
+
 	call waitsw
-	jp main
 
-text:
-	db $1B,"[1mFPGABoy Diagnostic ROM",$1B,"[0m",$0D,$0A,0
+	jr main
+
+signon:
+	db $0D,$0A,$1B,"[1mFPGABoy Diagnostic ROM",$1B,"[0m",$0D,$0A,0
 
+; Memory tester: writes h ^ l to all addresses from C000 to DF80.
 memtest:
 	ld hl,memteststr
 	call puts
 	
-	ld hl, $C000
+	ld hl, $C000		; Write loop
 .wr:
 	ld a,h
 	xor l
 	ld [hli],a
 	ld a, $DF
 	cp h
-	jp nz, .wr
+	jr nz, .wr
 	ld a, $80
 	cp l
-	jp nz, .wr
+	jr nz, .wr
 
-	ld hl, $C000
+	ld hl, $C000		; Read loop
 .rd:
 	ld a,h
 	xor l
 	ld b,a
 	ld a, [hli]
 	cp b
-	jp nz, .memfail
+	jr nz, .memfail
 	
 	ld a, $DF
 	cp h
-	jp nz, .rd
+	jr nz, .rd
 	ld a, $80
 	cp l
-	jp nz, .rd
+	jr nz, .rd
 	
-	ld hl, testokstr
+	ld hl, testokstr	; Say we're OK
 	call puts
 	ret
-.memfail:
-	@ decrement hl the easy way
+.memfail:			; Say we failed (sadface)
+	; decrement hl the easy way
 	ld a,[hld]
 	push hl
 	ld hl, failatstr
@@ -66,14 +73,14 @@ memtest:
 	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:
+
+puthex:				; Put two hex nibbles to the serial console.
 	push af
 	rra
 	rra
@@ -92,6 +99,7 @@ puthex:
 	call putc
 	ret
 
+; Wait for switches to be flipped on and off again.
 waitsw:
 	ld hl,waitswstr
 	call puts
@@ -105,16 +113,110 @@ waitsw:
 .loop1:
 	ld a,[c]
 	cp b
-	jp z,.loop1
+	jr z,.loop1
 .loop2:
 	ld a,[c]
 	cp b
-	jp nz,.loop2
+	jr nz,.loop2
 	ret
 
 waitswstr:
 	db "Diagnostic ROM complete; flip switches to nonzero and then to zero to reset.",$0D,$0A,0
 
+; Core instruction basic acceptance tests.
+insntest:
+	ld hl, .insnteststr
+	call puts
+	
+	; Test PUSH and POP.
+	ld b, $12
+	ld c, $34
+	ld d, $56
+	ld e, $78
+	push bc
+	pop de
+	ld hl, .pushpopfail
+	ld a, d
+	cp b
+	jr nz,.fail
+	ld a, e
+	cp c
+	jr nz,.fail
+	
+	; Test ALU (HL).
+	ld hl, .ff
+	ld a, $FF
+	xor [hl]
+	ld hl, .xorhlfail
+	jr nz, .fail
+	
+	; Test JP (HL)
+	ld hl, .jphl
+	jp [hl]
+	ld hl, .jphlfail
+	jr .fail
+	rst $00
+.jphl:
+
+	; Test JR
+	ld a, $FF
+	ld b, $00
+	cp b
+	jr nz,.jr
+	ld hl, .jrfail
+	jr .fail
+	rst $00
+.jr:
+	
+	; Test CP.
+	ld hl, .cpfail
+	ld a, $10
+	ld b, $20
+	cp b
+	jr nc,.fail
+	ld a, $20
+	ld b, $10
+	cp b
+	jr c,.fail
+	
+	; Test CPL
+	ld hl, .cplfail
+	ld a, $55
+	ld b, $AA
+	cpl
+	cp b
+	jr nz,.fail
+	
+	ld hl, .ok
+	call puts
+	ret
+.fail:
+	call puts
+	ld hl, .testfailed
+	call puts
+	ret
+.insnteststr:
+	db "Testing instructions... ",0
+.pushpopfail:
+	db "PUSH/POP",0
+.ff:
+	db $FF
+.xorhlfail:
+	db "XOR [HL]",0
+.jphlfail:
+	db "JP [HL]",0
+.jrfail:
+	db "JR",0
+.cpfail:
+	db "CP",0
+.cplfail:
+	db "CPL",0
+.testfailed:
+	db " test failed.",$0D,$0A,0
+.ok:
+	db "OK!",$0D,$0A,0
+
+; Serial port manipulation functions.
 putc:
 	push af
 	ld b, 0
@@ -122,7 +224,7 @@ putc:
 .waitport:
 	ld a,[c]
 	cp b
-	jp nz,.waitport
+	jr nz,.waitport
 	pop af
 	ld [c],a
 	ret
@@ -131,9 +233,6 @@ puts:
 	ld a, [hli]
 	ld b, $00
 	cp b
-	jp z, .done
+	ret z
 	call putc
-	jp puts
-.done:
-	ret
-
+	jr puts