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[PATCH v2 0/7] target/riscv: NaN-boxing for multiple precison

From: Richard Henderson
Subject: [PATCH v2 0/7] target/riscv: NaN-boxing for multiple precison
Date: Thu, 23 Jul 2020 17:28:00 -0700

This is my take on Liu Zhiwei's patch set:

This differs from Zhiwei's v1 in:

 * If a helper is involved, the helper does the boxing and unboxing.

 * Which leaves only LDW and FSGN*.S as the only instructions that
   are expanded inline which need to handle nanboxing.

 * All mention of RVD is dropped vs boxing.  This means that an
   RVF-only cpu will still generate and check nanboxes into the
   64-bit cpu_fpu slots.  There should be no way an RVF-only cpu
   can generate an unboxed cpu_fpu value.

   This choice is made to speed up the common case: RVF+RVD, so
   that we do not have to check whether RVD is enabled.

 * The translate.c primitives take TCGv values rather than fpu
   regno, which will make it possible to use them with RVV,
   since v0.9 does proper nanboxing.

 * I have adjusted the current naming to be float32 specific ("*_s"),
   to avoid confusion with the float16 data type supported by RVV.


LIU Zhiwei (2):
  target/riscv: Clean up fmv.w.x
  target/riscv: check before allocating TCG temps

Richard Henderson (5):
  target/riscv: Generate nanboxed results from fp helpers
  target/riscv: Generalize gen_nanbox_fpr to gen_nanbox_s
  target/riscv: Generate nanboxed results from trans_rvf.inc.c
  target/riscv: Check nanboxed inputs to fp helpers
  target/riscv: Check nanboxed inputs in trans_rvf.inc.c

 target/riscv/internals.h                |  16 ++++
 target/riscv/fpu_helper.c               | 102 ++++++++++++++++--------
 target/riscv/insn_trans/trans_rvd.inc.c |   8 +-
 target/riscv/insn_trans/trans_rvf.inc.c |  99 ++++++++++++++---------
 target/riscv/translate.c                |  29 +++++++
 5 files changed, 178 insertions(+), 76 deletions(-)


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