Make mod jet round the quotient with the active rounding mode#27
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The mod/mods jets hardcoded softfloat_round_minMag (truncation toward zero) when reducing x/n to an integer, while the Hoon reference rounds that quotient with `toi` under the active rounding mode. The two disagreed for any mode other than %z, and for negatives even under the default %n (e.g. 5 mod 3 = -1 under round-nearest, not 2). Use softfloat_roundingMode (already set by _set_rounding(rnd) in both the mod and mods wrappers) for the quotient round in u3qi_la_mod_i754 and u3qi_la_mods_i754, all four precisions, in all three jet files. The range/linspace ceil-count sites are left on minMag. Rename the now- misnamed floor_result/floor_float locals to quot_round/quot_round_f and correct the comments. Add a mod regression test (5 mod 3 = -1 under %n). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Summary
The
mod/modsjets reducedx/nto an integer with a hardcodedsoftfloat_round_minMag(truncation toward zero), but the Hoon reference rounds that quotient withtoiunder the active rounding mode (fun-scalar %mod, e.g. lagoon.hoon:1061). The two disagree for any mode other than%z, and even under the default%nfor negative quotients — e.g.5 mod 3 = 5 - 3·round(5/3) = -1under round-nearest, vs2under truncation.Per maintainer direction the jet should match Hoon (SoftBLAS is being aligned upstream similarly).
Fix
Use
softfloat_roundingMode— already established by_set_rounding(rnd)in both theu3wi_la_modandu3wi_la_modswrappers — for the quotient round inu3qi_la_mod_i754andu3qi_la_mods_i754(all four precisions), across all three jet files. The 8 mod/mods sites per file are changed; the range/linspaceceil-count sites stay onminMag(unrelated). The now-misnamedfloor_result/floor_floatlocals are renamed toquot_round/quot_round_f, and the "floor" comments corrected.Test
Added a
modregression test:5 mod 3 = -1under the default%nmode (the old truncating jet returned2).Note
This is a behavioral change to
modfor non-%zmodes and negatives. It aligns the jet with the Hoon reference; reviewers fixing SoftBLAS upstream should confirm the upstreammodmatches.🤖 Generated with Claude Code