From 354908cee1f7ff761b5fedbdb6376c378c10f941 Mon Sep 17 00:00:00 2001 From: Ian Jiang Date: Tue, 28 Jan 2020 08:37:07 +0800 Subject: [PATCH] riscv: Add helper to make NaN-boxing for FP register The function that makes NaN-boxing when a 32-bit value is assigned to a 64-bit FP register is split out to a helper gen_nanbox_fpr(). Then it is applied in translating of the FLW instruction. Signed-off-by: Ian Jiang Message-Id: <20200128003707.17028-1-ianjiang.ict@gmail.com> Reviewed-by: Alistair Francis Reviewed-by: Richard Henderson Signed-off-by: Alistair Francis --- target/riscv/insn_trans/trans_rvf.inc.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/target/riscv/insn_trans/trans_rvf.inc.c b/target/riscv/insn_trans/trans_rvf.inc.c index e23cd639a6..3bfd8881e7 100644 --- a/target/riscv/insn_trans/trans_rvf.inc.c +++ b/target/riscv/insn_trans/trans_rvf.inc.c @@ -23,6 +23,20 @@ return false; \ } while (0) +/* + * RISC-V requires NaN-boxing of narrower width floating + * point values. This applies when a 32-bit value is + * assigned to a 64-bit FP register. Thus this does not + * apply when the RVD extension is not present. + */ +static void gen_nanbox_fpr(DisasContext *ctx, int regno) +{ + if (has_ext(ctx, RVD)) { + tcg_gen_ori_i64(cpu_fpr[regno], cpu_fpr[regno], + MAKE_64BIT_MASK(32, 32)); + } +} + static bool trans_flw(DisasContext *ctx, arg_flw *a) { TCGv t0 = tcg_temp_new(); @@ -32,8 +46,7 @@ static bool trans_flw(DisasContext *ctx, arg_flw *a) tcg_gen_addi_tl(t0, t0, a->imm); tcg_gen_qemu_ld_i64(cpu_fpr[a->rd], t0, ctx->mem_idx, MO_TEUL); - /* RISC-V requires NaN-boxing of narrower width floating point values */ - tcg_gen_ori_i64(cpu_fpr[a->rd], cpu_fpr[a->rd], 0xffffffff00000000ULL); + gen_nanbox_fpr(ctx, a->rd); tcg_temp_free(t0); mark_fs_dirty(ctx);