ref: 222434e8ae55fc61233e610b516d186465a0e4ad
parent: be70b4c13092fa390eaddd717aabfd841804ae59
parent: 28e223d9889f046f0316f5f61c463caf88a212ce
author: Bryan Bishop <[email protected]>
date: Wed May 23 08:01:26 EDT 2012
Merge pull request #10 from Zhorken/rebased More little things
--- a/main.asm
+++ b/main.asm
@@ -6,13 +6,52 @@
jumptextfaceplayer $26f2
; 0x26f2
-INCBIN "baserom.gbc",$26f2,$94f
+INCBIN "baserom.gbc",$26f2,$937
-ByteFill: ; 0x3041
-; fill BC bytes with the value of A, starting at HL
- inc b ; we bail *when* b hits 0, so include the last run
+CopyBytes: ; 0x3026
+; copy bc bytes from hl to de
+ inc b ; we bail the moment b hits 0, so include the last run
inc c ; same thing; include last byte
jr .HandleLoop
+.CopyByte
+ ld a, [hli]
+ ld [de], a
+ inc de
+.HandleLoop
+ dec c
+ jr nz, .CopyByte
+ dec b
+ jr nz, .CopyByte
+ ret
+
+SwapBytes: ; 0x3034
+; swap bc bytes between hl and de
+.Loop
+ ; stash [hl] away on the stack
+ ld a, [hl]
+ push af
+
+ ; copy a byte from [de] to [hl]
+ ld a, [de]
+ ld [hli], a
+
+ ; retrieve the previous value of [hl]; put it in [de]
+ pop af
+ ld [de], a
+
+ ; handle loop stuff
+ inc de
+ dec bc
+ ld a, b
+ or c
+ jr nz, .Loop
+ ret
+
+ByteFill: ; 0x3041
+; fill bc bytes with the value of a, starting at hl
+ inc b ; we bail the moment b hits 0, so include the last run
+ inc c ; same thing; include last byte
+ jr .HandleLoop
.PutByte
ld [hli], a
.HandleLoop
@@ -43,7 +82,27 @@
ld a, [$ff00+$8b]
ret
-INCBIN "baserom.gbc",$305d,$30fe-$305d
+GetFarHalfword: ; 0x305d
+; retrieve a halfword from a:hl, and return it in hl.
+ ; bankswitch to new bank
+ ld [$ff00+$8b], a
+ ld a, [$ff00+$9d]
+ push af
+ ld a, [$ff00+$8b]
+ rst $10
+
+ ; get halfword from new bank, put it in hl
+ ld a, [hli]
+ ld h, [hl]
+ ld l, a
+
+ ; bankswitch to previous bank and return
+ pop af
+ rst $10
+ ret
+; 0x306b
+
+INCBIN "baserom.gbc",$306b,$30fe-$306b
AddNTimes: ; 0x30fe
and a