[00xDisaster]

What

Add _Divide, _FDivide, _Recip and _FRecip, the double and float Dinkumware division and reciprocal helpers. They use IEEE division and reciprocal semantics; tests cover quotients, signed zero, signed infinity, NaN and infinity operands. Exact console results, signaling-NaN handling and floating-point exception behavior remain unverified and are recorded in the libc debt entry.

The declarations live in Api.hpp; no other open PR implements these four exports.

Tested

Linux CachyOS 7.3.0-2-cachyos, GCC 16.2.1. Base upstream/main bd8e13428a; head 72583a0b20.

The approved commit 5ae2d41c23 differs from the pre-rebase head c777042410 only by the removal of two trailing blank lines at the ends of the source and test files. Rebased after main advanced: the only conflict was the adjacent _FSinh/_FCosh debt entry; main's measured version and this PR's division entry are both preserved, and no code or test statements changed.

• cmake --build build --target guest_dinkumware_internals_tests guest_math_tests guest_math_exact_tests libs --parallel 8: passed.
• ctest --test-dir build -R '^(guest_dinkumware_internals|guest_math|guest_math_exact)$' --output-on-failure: 3/3 passed.
• guest_dinkumware_internals covers double and float division and reciprocal results, signed zero, signed infinity, NaN and infinity operands.
• guest_math and guest_math_exact are the neighboring libm suites and pass unchanged.
• tools/check_conventions.py --base upstream/main --head HEAD and git diff --check: clean.
• GPUs tested: n/a.

Checklist

• Based on current main; no other open PR implements the same functions
• One topic per PR; follow-ups go in a new PR
• No comments in code except technical debt
• Unimplemented paths throw (NotImplemented_nid_no_patch); silent stubs are listed under Silent stubs in their library's technical debt file
• No notes, investigation .md files or images added to the repository (attach them to this PR)
• New third-party code is a submodule built from source
• Generic behaviour, not specific to one title
• Depends on: none
• Fixes: none
• Unblocks: none
• GPUs tested: n/a
• AI-assisted: no

[github-actions]

Progress report (50a4f82 → 72583a0)

📈 System libraries: 48.87% (+0.01%, +4 implemented functions)

✅ 4 implemented

Library	Name
libc	_Divide_nid_postfix
libc	_FDivide_nid_postfix
libc	_FRecip_nid_postfix
libc	_Recip_nid_postfix

Changed libraries (implemented exports)

Library	Before	After	Change
libc	1337/1348 (99.18%)	1341/1352 (99.19%)	+0.00 pp

[MarcZX10]

Reviewed exact head 5ae2d41. The four helpers are narrowly scoped IEEE division/reciprocal wrappers, declarations are in the canonical API header, and the console-specific floating-point gaps are recorded in libc debt. Locally, both changed C++ translation units compile with GCC 12.2 using -Wall -Wextra -Werror; a focused harness linked to the exact implementation and passed quotient, signed-zero, infinity, and NaN cases. diff --check and the current-main conventions check pass. I could not configure the integrated libc test target locally because this environment lacks SDL2/XRandR development support; the PR reports its focused CTest run, and the hosted conventions/intake checks pass. The remaining console-specific behavior is explicitly unverified in the debt entry.

[github-actions]

Other open pull requests touch the same code. Merging one will break the other, or both implement the same thing. If this one builds on them, list them in Depends on.

Pull request	Conflicting files (lines on main)	Same exports	Same new files
PR 10345	docs/dev/debt/libc.md L70-71

Some comparisons could not be completed because a pull request conflicts with the base branch. Review these shared files manually before concluding that there is no overlap.

Pull request	Shared files not compared
PR 3965	docs/dev/debt/libc.md
PR 5021	docs/dev/debt/libc.md
PR 5303	docs/dev/debt/libc.md
PR 6713	docs/dev/debt/libc.md
PR 7081	docs/dev/debt/libc.md
PR 7386	docs/dev/debt/libc.md
PR 7447	docs/dev/debt/libc.md
PR 7544	docs/dev/debt/libc.md
PR 7648	docs/dev/debt/libc.md
PR 7715	docs/dev/debt/libc.md
PR 8150	docs/dev/debt/libc.md
PR 8417	docs/dev/debt/libc.md
PR 9087	docs/dev/debt/libc.md
PR 9269	docs/dev/debt/libc.md
PR 9340	docs/dev/debt/libc.md
PR 9371	docs/dev/debt/libc.md
PR 9408	docs/dev/debt/libc.md
PR 9447	docs/dev/debt/libc.md
PR 9499	docs/dev/debt/libc.md
PR 9526	docs/dev/debt/libc.md
PR 9527	docs/dev/debt/libc.md
PR 9552	docs/dev/debt/libc.md
PR 9648	docs/dev/debt/libc.md
PR 9669	docs/dev/debt/libc.md
PR 9784	docs/dev/debt/libc.md
PR 9863	docs/dev/debt/libc.md
PR 9873	docs/dev/debt/libc.md
PR 9929	docs/dev/debt/libc.md
PR 9973	docs/dev/debt/libc.md
PR 10007	docs/dev/debt/libc.md
PR 10234	docs/dev/debt/libc.md
PR 10245	docs/dev/debt/libc.md
PR 10316	docs/dev/debt/libc.md
PR 10317	docs/dev/debt/libc.md
PR 10321	docs/dev/debt/libc.md
PR 10325	docs/dev/debt/libc.md
PR 10328	docs/dev/debt/libc.md
PR 10354	docs/dev/debt/libc.md
PR 10405	docs/dev/debt/libc.md
PR 10460	docs/dev/debt/libc.md
PR 10468	docs/dev/debt/libc.md
PR 10506	docs/dev/debt/libc.md
PR 10510	docs/dev/debt/libc.md

[MarcZX10]

The new head differs from the previously reviewed commit only by removing trailing blank lines in the implementation and test files; no executable code or test assertions changed. I rechecked the exact head, git diff --check, and the conventions checker (all pass). The prior GCC 12.2 -Wall -Wextra -Werror compile and focused exact-source harness remain applicable to the unchanged code. Hosted eligibility, conventions, labels, report, Ubuntu/Windows relinker, ASAN, Ubuntu register-context and macOS write-watch checks pass; macOS relinker and Intel register-context checks are still queued, and product jobs are path-skipped.

[00xDisaster]

@MarcZX10 I rebased this onto current main bd8e13428a. The only conflict was the adjacent measured _FSinh/_FCosh debt entry; I preserved both entries, and no code or tests changed. The pre-rebase head differed from your approved 5ae2d41c23 only by two trailing blank lines. At 72583a0b20, guest_dinkumware_internals, guest_math and guest_math_exact pass 3/3, and conventions plus git diff --check are clean. Could you re-approve this head? Checks are running.

[MarcZX10]

Reviewed the rebased head 72583a0b20ceb65ebaf630775ce9c0e42137a625. The four wrappers use native IEEE division/reciprocal operations, and the tests cover finite values, signed zero, infinities and NaNs; the remaining console/FENV uncertainty is recorded in debt. The PR reports 3/3 focused Linux tests on this head. Current hosted relinker, ASAN, register-context and write-watch jobs pass; platform product jobs are skipped. git diff --check against current main is clean, and the hosted conventions check passes. I also manually checked the #10345 overlap: it changes the fmod/fmodf debt entry, with no implementation/export duplication; preserve both debt entries if the adjacent documentation hunk conflicts during merge.