[fatdrvce] converted division by a power of two into a bitshift#791
Draft
ZERICO2005 wants to merge 6 commits intomasterfrom
Draft
[fatdrvce] converted division by a power of two into a bitshift#791ZERICO2005 wants to merge 6 commits intomasterfrom
ZERICO2005 wants to merge 6 commits intomasterfrom
Conversation
mateoconlechuga
force-pushed
the
fatdrvce_use_shift
branch
from
3281b13 to
434119f
Compare
mateoconlechuga
temporarily deployed
to
Autotester
GitHub Actions
Inactive
mateoconlechuga
temporarily deployed
to
Autotester
GitHub Actions
Inactive
mateoconlechuga
temporarily deployed
to
Autotester
GitHub Actions
Inactive
mateoconlechuga
temporarily deployed
to
Autotester
GitHub Actions
Inactive
mateoconlechuga
temporarily deployed
to
Autotester
GitHub Actions
Inactive
mateoconlechuga
temporarily deployed
to
Autotester
GitHub Actions
Inactive
mateoconlechuga
temporarily deployed
to
Autotester
GitHub Actions
Inactive
mateoconlechuga
temporarily deployed
to
Autotester
GitHub Actions
Inactive
runer112
reviewed
Apr 18, 2026
Comment on lines
2522
to
2541
| compare_auhl_zero | ||
| ret z | ||
| ld e,a | ||
| push hl,de | ||
| xor a,a | ||
| ld bc,512 | ||
| push bc | ||
| call ti._lremu | ||
| compare_hl_zero | ||
| pop bc,de,hl | ||
| ; test if the low 9 bits are non-zero | ||
| inc l | ||
| dec l | ||
| jr nz,.round_up | ||
| bit 0,h | ||
| .round_up: | ||
| push af | ||
| xor a,a | ||
| call ti._ldivu | ||
| push hl | ||
| pop bc | ||
| ld l,9 | ||
| call ti._lshru | ||
| push bc | ||
| pop hl | ||
| pop af | ||
| ld a,0 | ||
| ret z | ||
| ; round up | ||
| inc hl |
Member
There was a problem hiding this comment.
; if A:UHL == 0, abort
compare_hl_zero
jr nz, .dec_hl
or a, a
ret z
; A:UHL--
dec a
.dec_hl:
dec hl
; A:UHL /= 512
push hl
pop bc
ld l, 9
call ti._lshru
push bc
pop hl
; A:UHL++
inc hl
ret
Contributor
Author
There was a problem hiding this comment.
Good point. That trick works since we have already filtered out the A:UHL == 0 case
Co-authored-by: Zachary Wassall <runer112@gmail.com>
ZERICO2005
force-pushed
the
fatdrvce_use_shift
branch
from
434119f to
65392f1
Compare
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
TL:DR turns 32bit division into a bitshift
Resolves #757