fpu: round integer-to-float conversions with RMM ties-away - #269
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fpu: round integer-to-float conversions with RMM ties-away#269carlosqwqqwq wants to merge 1 commit into
carlosqwqqwq wants to merge 1 commit into
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fpu: round integer-to-float conversions with RMM ties-away
Fixes #264
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Description
The integer-to-float conversions (
fcvt.s.w[u]/l[u],fcvt.d.w[u]/l[u]) use plain host casts, which only provide RNE. Under RMM (staticrm=RMMordyn + frm=RMM) the exact-halfway cases must round away from zero; the current code returns the RNE neighbour. Add magnitude-based RMM conversion helpers insrc/util/fpu_lib.h(exact for inputs that fit, otherwise one rounded significand with ties-away and explicitNX), and select them fromsrc/cpu/riscv_fpu.cwhen the effective mode is RMM.fcvt.d.lalso now passes the resolved dynamic mode to the existingfpu_round_i64_to_f64. This is a separate source path from the float-to-integer conversion fix (the conversion direction and helpers differ), from the arithmetic RMM synthesis, and from the FMA rounding repairs.