diff options
Diffstat (limited to 'basics/chr-ram.s')
| -rw-r--r-- | basics/chr-ram.s | 37 |
1 files changed, 13 insertions, 24 deletions
diff --git a/basics/chr-ram.s b/basics/chr-ram.s index 20e1b30..bb2186e 100644 --- a/basics/chr-ram.s +++ b/basics/chr-ram.s @@ -29,7 +29,8 @@ .segment "BANK0" -chr: .incbin "../assets/basic.chr" +chr: + .incbin "../assets/basic.chr" .segment "BANK1" .byte $00 @@ -56,33 +57,18 @@ chr: .incbin "../assets/basic.chr" .segment "FIXED" ;;; -;; Bank switching code as with `basics/unrom.s`. Not used here. - -banktable: - .byte $00, $01, $02, $03, $04, $05, $06 - -m_current_bank = $00 - -bankswitch: - sty m_current_bank -bankswitch_nosave: - tya - sta banktable, y - rts - -;;; ;; From here on the code is basically the same as `basics/sprite.s`, but with a ;; special twist that will be commented in. For comments on the rest of the code ;; just check `basics/sprite.s`. -reset: +.proc reset sei cld - ldx #$40 + ldx #$FF stx $4017 - ldx #$ff + ldx #$FF txs inx stx $2000 @@ -139,6 +125,7 @@ reset: bne @palettes_reset_loop jmp main +.endproc ;;; ;; Transfer the CHR data from PRG-ROM into RAM. @@ -166,17 +153,17 @@ reset: ;; - x contains the number of 256-byte pages to copy. ;; - y will index within the page ($00-$FF). ldx #32 -loop: +@loop: ;; First part of the loop: copy each byte of the current page. lda ($00), y sta $2007 iny - bne loop + bne @loop ;; Go to the next page and repeat the first part of the loop. inc $01 dex - bne loop + bne @loop rts .endproc @@ -274,7 +261,7 @@ initial_sprite_data: .byte $B0, $00, %01000000, $82 .endproc -nmi: +.proc nmi bit $20 bpl @next @@ -305,6 +292,8 @@ nmi: pla @next: rti +.endproc -irq: +.proc irq rti +.endproc |