izaya/collapseos
1
0
Fork 0
mirror of https://github.com/hsoft/collapseos.git synced 2025-04-11 03:38:15 +10:00
Code Issues Releases Wiki Activity

Fixed comments

Browse Source 
I agree the comments I had weren't very useful in terms of understanding the code, and I also agree the comments I removed didn't need removing. I've edited them a little because I feel like it's clearer to refer to the nibbles of what will be the result rather than the bytes of what was the data being parsed, but I'd like to hear your opinion on that.
This commit is contained in:
Clanmaster21 2020-01-07 15:33:56 +00:00 committed by GitHub
parent 423460cc47
commit fca0244c68
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 9 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
kernel/parse.asm
View File

@ -44,27 +44,25 @@ parseHex:
parseHexPair:
ld a, (hl)
call parseHex
ret c ; faster and smaller than a conditional jump
; by delaying this push, we can use a conditional return above
ret c ; if there's an error, return
push bc
ld b, a
ld b, a ; save MSN (Most Significant Nibble)
inc hl
ld a, (hl)
cp 0x21
jr c, .single
jr c, .single ; special char? single digit
call parseHex
jr c, .end
ld c, a
jr c, .end ; if error, go to end
ld c, a ; save LSN (Least Significant Nibble)
ld a, b
; by delaying shifting until the end, we save bytes in the single case.
rla \ rla \ rla \ rla
or c
rla \ rla \ rla \ rla ; left shift into MSN (also zeroes LSN)
or c ; join MSN + LSN. we're done!
.end:
.end:
pop bc
ret
.single:
.single:
ld a, b
dec hl
pop bc