+++ /dev/null
- 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
-