From d4893b01d23060845ee3855bc96626e16aad9ab5 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Tue, 11 Jun 2019 16:39:49 +0100 Subject: [PATCH] target/arm: Convert VFP fused multiply-add insns to decodetree Convert the VFP fused multiply-add instructions (VFNMA, VFNMS, VFMA, VFMS) to decodetree. Note that in the old decode structure we were implementing these to honour the VFP vector stride/length. These instructions were introduced in VFPv4, and in the v7A architecture they are UNPREDICTABLE if the vector stride or length are non-zero. In v8A they must UNDEF if stride or length are non-zero, like all VFP instructions; we choose to UNDEF always. Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson --- target/arm/translate-vfp.inc.c | 121 +++++++++++++++++++++++++++++++++ target/arm/translate.c | 53 +-------------- target/arm/vfp.decode | 9 +++ 3 files changed, 131 insertions(+), 52 deletions(-) diff --git a/target/arm/translate-vfp.inc.c b/target/arm/translate-vfp.inc.c index 6af99605d5..ba6506a378 100644 --- a/target/arm/translate-vfp.inc.c +++ b/target/arm/translate-vfp.inc.c @@ -1481,3 +1481,124 @@ static bool trans_VDIV_dp(DisasContext *s, arg_VDIV_sp *a) { return do_vfp_3op_dp(s, gen_helper_vfp_divd, a->vd, a->vn, a->vm, false); } + +static bool trans_VFM_sp(DisasContext *s, arg_VFM_sp *a) +{ + /* + * VFNMA : fd = muladd(-fd, fn, fm) + * VFNMS : fd = muladd(-fd, -fn, fm) + * VFMA : fd = muladd( fd, fn, fm) + * VFMS : fd = muladd( fd, -fn, fm) + * + * These are fused multiply-add, and must be done as one floating + * point operation with no rounding between the multiplication and + * addition steps. NB that doing the negations here as separate + * steps is correct : an input NaN should come out with its sign + * bit flipped if it is a negated-input. + */ + TCGv_ptr fpst; + TCGv_i32 vn, vm, vd; + + /* + * Present in VFPv4 only. + * In v7A, UNPREDICTABLE with non-zero vector length/stride; from + * v8A, must UNDEF. We choose to UNDEF for both v7A and v8A. + */ + if (!arm_dc_feature(s, ARM_FEATURE_VFP4) || + (s->vec_len != 0 || s->vec_stride != 0)) { + return false; + } + + if (!vfp_access_check(s)) { + return true; + } + + vn = tcg_temp_new_i32(); + vm = tcg_temp_new_i32(); + vd = tcg_temp_new_i32(); + + neon_load_reg32(vn, a->vn); + neon_load_reg32(vm, a->vm); + if (a->o2) { + /* VFNMS, VFMS */ + gen_helper_vfp_negs(vn, vn); + } + neon_load_reg32(vd, a->vd); + if (a->o1 & 1) { + /* VFNMA, VFNMS */ + gen_helper_vfp_negs(vd, vd); + } + fpst = get_fpstatus_ptr(0); + gen_helper_vfp_muladds(vd, vn, vm, vd, fpst); + neon_store_reg32(vd, a->vd); + + tcg_temp_free_ptr(fpst); + tcg_temp_free_i32(vn); + tcg_temp_free_i32(vm); + tcg_temp_free_i32(vd); + + return true; +} + +static bool trans_VFM_dp(DisasContext *s, arg_VFM_sp *a) +{ + /* + * VFNMA : fd = muladd(-fd, fn, fm) + * VFNMS : fd = muladd(-fd, -fn, fm) + * VFMA : fd = muladd( fd, fn, fm) + * VFMS : fd = muladd( fd, -fn, fm) + * + * These are fused multiply-add, and must be done as one floating + * point operation with no rounding between the multiplication and + * addition steps. NB that doing the negations here as separate + * steps is correct : an input NaN should come out with its sign + * bit flipped if it is a negated-input. + */ + TCGv_ptr fpst; + TCGv_i64 vn, vm, vd; + + /* + * Present in VFPv4 only. + * In v7A, UNPREDICTABLE with non-zero vector length/stride; from + * v8A, must UNDEF. We choose to UNDEF for both v7A and v8A. + */ + if (!arm_dc_feature(s, ARM_FEATURE_VFP4) || + (s->vec_len != 0 || s->vec_stride != 0)) { + return false; + } + + /* UNDEF accesses to D16-D31 if they don't exist. */ + if (!dc_isar_feature(aa32_fp_d32, s) && ((a->vd | a->vn | a->vm) & 0x10)) { + return false; + } + + if (!vfp_access_check(s)) { + return true; + } + + vn = tcg_temp_new_i64(); + vm = tcg_temp_new_i64(); + vd = tcg_temp_new_i64(); + + neon_load_reg64(vn, a->vn); + neon_load_reg64(vm, a->vm); + if (a->o2) { + /* VFNMS, VFMS */ + gen_helper_vfp_negd(vn, vn); + } + neon_load_reg64(vd, a->vd); + if (a->o1 & 1) { + /* VFNMA, VFNMS */ + gen_helper_vfp_negd(vd, vd); + } + fpst = get_fpstatus_ptr(0); + gen_helper_vfp_muladdd(vd, vn, vm, vd, fpst); + neon_store_reg64(vd, a->vd); + + tcg_temp_free_ptr(fpst); + tcg_temp_free_i64(vn); + tcg_temp_free_i64(vm); + tcg_temp_free_i64(vd); + + return true; +} diff --git a/target/arm/translate.c b/target/arm/translate.c index 48981af862..58a0dfda68 100644 --- a/target/arm/translate.c +++ b/target/arm/translate.c @@ -3093,7 +3093,7 @@ static int disas_vfp_insn(DisasContext *s, uint32_t insn) rn = VFP_SREG_N(insn); switch (op) { - case 0 ... 8: + case 0 ... 13: /* Already handled by decodetree */ return 1; default: @@ -3279,57 +3279,6 @@ static int disas_vfp_insn(DisasContext *s, uint32_t insn) for (;;) { /* Perform the calculation. */ switch (op) { - case 10: /* VFNMA : fd = muladd(-fd, fn, fm) */ - case 11: /* VFNMS : fd = muladd(-fd, -fn, fm) */ - case 12: /* VFMA : fd = muladd( fd, fn, fm) */ - case 13: /* VFMS : fd = muladd( fd, -fn, fm) */ - /* These are fused multiply-add, and must be done as one - * floating point operation with no rounding between the - * multiplication and addition steps. - * NB that doing the negations here as separate steps is - * correct : an input NaN should come out with its sign bit - * flipped if it is a negated-input. - */ - if (!arm_dc_feature(s, ARM_FEATURE_VFP4)) { - return 1; - } - if (dp) { - TCGv_ptr fpst; - TCGv_i64 frd; - if (op & 1) { - /* VFNMS, VFMS */ - gen_helper_vfp_negd(cpu_F0d, cpu_F0d); - } - frd = tcg_temp_new_i64(); - tcg_gen_ld_f64(frd, cpu_env, vfp_reg_offset(dp, rd)); - if (op & 2) { - /* VFNMA, VFNMS */ - gen_helper_vfp_negd(frd, frd); - } - fpst = get_fpstatus_ptr(0); - gen_helper_vfp_muladdd(cpu_F0d, cpu_F0d, - cpu_F1d, frd, fpst); - tcg_temp_free_ptr(fpst); - tcg_temp_free_i64(frd); - } else { - TCGv_ptr fpst; - TCGv_i32 frd; - if (op & 1) { - /* VFNMS, VFMS */ - gen_helper_vfp_negs(cpu_F0s, cpu_F0s); - } - frd = tcg_temp_new_i32(); - tcg_gen_ld_f32(frd, cpu_env, vfp_reg_offset(dp, rd)); - if (op & 2) { - gen_helper_vfp_negs(frd, frd); - } - fpst = get_fpstatus_ptr(0); - gen_helper_vfp_muladds(cpu_F0s, cpu_F0s, - cpu_F1s, frd, fpst); - tcg_temp_free_ptr(fpst); - tcg_temp_free_i32(frd); - } - break; case 14: /* fconst */ if (!arm_dc_feature(s, ARM_FEATURE_VFP3)) { return 1; diff --git a/target/arm/vfp.decode b/target/arm/vfp.decode index de305f60e1..37eec0e131 100644 --- a/target/arm/vfp.decode +++ b/target/arm/vfp.decode @@ -142,3 +142,12 @@ VDIV_sp ---- 1110 1.00 .... .... 1010 .0.0 .... \ vm=%vm_sp vn=%vn_sp vd=%vd_sp VDIV_dp ---- 1110 1.00 .... .... 1011 .0.0 .... \ vm=%vm_dp vn=%vn_dp vd=%vd_dp + +VFM_sp ---- 1110 1.01 .... .... 1010 . o2:1 . 0 .... \ + vm=%vm_sp vn=%vn_sp vd=%vd_sp o1=1 +VFM_dp ---- 1110 1.01 .... .... 1011 . o2:1 . 0 .... \ + vm=%vm_dp vn=%vn_dp vd=%vd_dp o1=1 +VFM_sp ---- 1110 1.10 .... .... 1010 . o2:1 . 0 .... \ + vm=%vm_sp vn=%vn_sp vd=%vd_sp o1=2 +VFM_dp ---- 1110 1.10 .... .... 1011 . o2:1 . 0 .... \ + vm=%vm_dp vn=%vn_dp vd=%vd_dp o1=2