+++ /dev/null
- SECTION "a",HOME
-
-main:
- ld c, $51 ; Note that we are alive.
- ld a, $FF
- ld [c],a
-
- ld sp, $DFFF
-
- ld hl, signon
- call puts
-
- call memtest
-
- call insntest
-
- call waitsw
-
- jp 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 ; Write loop
-.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 ; Read loop
-.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 ; Say we're OK
- call puts
- ret
-.memfail: ; Say we failed (sadface)
- ; 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: ; Put two hex nibbles to the serial console.
- 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
-
-; Wait for switches to be flipped on and off again.
-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
-
-; 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
- jp nz,.fail
- ld a, e
- cp c
- jp nz,.fail
-
- ; Test ALU (HL).
- ld hl, .ff
- ld a, $FF
- xor [hl]
- ld hl, .xorhlfail
- jp nz, .fail
-
- ; Test CP.
- ld hl, .cpfail
- ld a, $10
- ld b, $20
- cp b
- jp nc,.fail
- ld a, $20
- ld b, $10
- cp b
- jp c,.fail
-
- ; Test CPL
- ld hl, .cplfail
- ld a, $55
- ld b, $AA
- cpl
- cp b
- jp nz,.fail
-
- ld hl, .ok
- call puts
- ret
-.fail:
- call puts
- ret
-.insnteststr:
- db "Testing instructions... ",$0
-.pushpopfail:
- db "PUSH/POP test failed.",$0D,$0A,0
-.ff:
- db $FF
-.xorhlfail:
- db "XOR [HL] test failed.",$0D,$0A,0
-.cpfail:
- db "CP test failed.",$0D,$0A,0
-.cplfail:
- db "CPL test failed.",$0D,$0A,0
-.ok:
- db "OK!",$0D,$0A,0
-
-; Serial port manipulation functions.
-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
-
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