Commit 564a0632 authored by Richard Henderson's avatar Richard Henderson Committed by Peter Maydell
Browse files

target/arm: Implement FCVT (scalar, integer) for fp16 



Cc: qemu-stable@nongnu.org
Reviewed-by: default avatarAlex Bennée <alex.bennee@linaro.org>
Signed-off-by: default avatarRichard Henderson <richard.henderson@linaro.org>
Tested-by: default avatarAlex Bennée <alex.bennee@linaro.org>
Message-id: 20180512003217.9105-4-richard.henderson@linaro.org
Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
parent 8c738d43

target/arm/helper.c

+36 −2
Original line number Diff line number Diff line
@@ -11427,8 +11427,12 @@ VFP_CONV_FIX_A64(uq, s, 32, 64, uint64) 
#undef VFP_CONV_FIX_A64



/* Conversion to/from f16 can overflow to infinity before/after scaling.

 * Therefore we convert to f64 (which does not round), scale,

 * and then convert f64 to f16 (which may round).

 * Therefore we convert to f64, scale, and then convert f64 to f16; or

 * vice versa for conversion to integer.

 *

 * For 16- and 32-bit integers, the conversion to f64 never rounds.

 * For 64-bit integers, any integer that would cause rounding will also

 * overflow to f16 infinity, so there is no double rounding problem.

 */



static float16 do_postscale_fp16(float64 f, int shift, float_status *fpst)
@@ -11446,6 +11450,16 @@ float16 HELPER(vfp_ultoh)(uint32_t x, uint32_t shift, void *fpst) 
    return do_postscale_fp16(uint32_to_float64(x, fpst), shift, fpst);

}



float16 HELPER(vfp_sqtoh)(uint64_t x, uint32_t shift, void *fpst)

{

    return do_postscale_fp16(int64_to_float64(x, fpst), shift, fpst);

}



float16 HELPER(vfp_uqtoh)(uint64_t x, uint32_t shift, void *fpst)

{

    return do_postscale_fp16(uint64_to_float64(x, fpst), shift, fpst);

}



static float64 do_prescale_fp16(float16 f, int shift, float_status *fpst)

{

    if (unlikely(float16_is_any_nan(f))) {
@@ -11475,6 +11489,26 @@ uint32_t HELPER(vfp_touhh)(float16 x, uint32_t shift, void *fpst) 
    return float64_to_uint16(do_prescale_fp16(x, shift, fpst), fpst);

}



uint32_t HELPER(vfp_toslh)(float16 x, uint32_t shift, void *fpst)

{

    return float64_to_int32(do_prescale_fp16(x, shift, fpst), fpst);

}



uint32_t HELPER(vfp_toulh)(float16 x, uint32_t shift, void *fpst)

{

    return float64_to_uint32(do_prescale_fp16(x, shift, fpst), fpst);

}



uint64_t HELPER(vfp_tosqh)(float16 x, uint32_t shift, void *fpst)

{

    return float64_to_int64(do_prescale_fp16(x, shift, fpst), fpst);

}



uint64_t HELPER(vfp_touqh)(float16 x, uint32_t shift, void *fpst)

{

    return float64_to_uint64(do_prescale_fp16(x, shift, fpst), fpst);

}



/* Set the current fp rounding mode and return the old one.

 * The argument is a softfloat float_round_ value.

 */

target/arm/helper.h

+6 −0
Original line number Diff line number Diff line
@@ -151,6 +151,10 @@ DEF_HELPER_3(vfp_touhd_round_to_zero, i64, f64, i32, ptr) 
DEF_HELPER_3(vfp_tould_round_to_zero, i64, f64, i32, ptr)

DEF_HELPER_3(vfp_touhh, i32, f16, i32, ptr)

DEF_HELPER_3(vfp_toshh, i32, f16, i32, ptr)

DEF_HELPER_3(vfp_toulh, i32, f16, i32, ptr)

DEF_HELPER_3(vfp_toslh, i32, f16, i32, ptr)

DEF_HELPER_3(vfp_touqh, i64, f16, i32, ptr)

DEF_HELPER_3(vfp_tosqh, i64, f16, i32, ptr)

DEF_HELPER_3(vfp_toshs, i32, f32, i32, ptr)

DEF_HELPER_3(vfp_tosls, i32, f32, i32, ptr)

DEF_HELPER_3(vfp_tosqs, i64, f32, i32, ptr)
@@ -177,6 +181,8 @@ DEF_HELPER_3(vfp_ultod, f64, i64, i32, ptr) 
DEF_HELPER_3(vfp_uqtod, f64, i64, i32, ptr)

DEF_HELPER_3(vfp_sltoh, f16, i32, i32, ptr)

DEF_HELPER_3(vfp_ultoh, f16, i32, i32, ptr)

DEF_HELPER_3(vfp_sqtoh, f16, i64, i32, ptr)

DEF_HELPER_3(vfp_uqtoh, f16, i64, i32, ptr)



DEF_HELPER_FLAGS_2(set_rmode, TCG_CALL_NO_RWG, i32, i32, ptr)

DEF_HELPER_FLAGS_2(set_neon_rmode, TCG_CALL_NO_RWG, i32, i32, env)

target/arm/translate-a64.c

+80 −16
Original line number Diff line number Diff line
@@ -5511,11 +5511,11 @@ static void handle_fpfpcvt(DisasContext *s, int rd, int rn, int opcode, 
                           bool itof, int rmode, int scale, int sf, int type)

{

    bool is_signed = !(opcode & 1);

    bool is_double = type;

    TCGv_ptr tcg_fpstatus;

    TCGv_i32 tcg_shift;

    TCGv_i32 tcg_shift, tcg_single;

    TCGv_i64 tcg_double;



    tcg_fpstatus = get_fpstatus_ptr(false);

    tcg_fpstatus = get_fpstatus_ptr(type == 3);



    tcg_shift = tcg_const_i32(64 - scale);
@@ -5533,8 +5533,9 @@ static void handle_fpfpcvt(DisasContext *s, int rd, int rn, int opcode, 
            tcg_int = tcg_extend;

        }



        if (is_double) {

            TCGv_i64 tcg_double = tcg_temp_new_i64();

        switch (type) {

        case 1: /* float64 */

            tcg_double = tcg_temp_new_i64();

            if (is_signed) {

                gen_helper_vfp_sqtod(tcg_double, tcg_int,

                                     tcg_shift, tcg_fpstatus);
@@ -5544,8 +5545,10 @@ static void handle_fpfpcvt(DisasContext *s, int rd, int rn, int opcode, 
            }

            write_fp_dreg(s, rd, tcg_double);

            tcg_temp_free_i64(tcg_double);

        } else {

            TCGv_i32 tcg_single = tcg_temp_new_i32();

            break;



        case 0: /* float32 */

            tcg_single = tcg_temp_new_i32();

            if (is_signed) {

                gen_helper_vfp_sqtos(tcg_single, tcg_int,

                                     tcg_shift, tcg_fpstatus);
@@ -5555,6 +5558,23 @@ static void handle_fpfpcvt(DisasContext *s, int rd, int rn, int opcode, 
            }

            write_fp_sreg(s, rd, tcg_single);

            tcg_temp_free_i32(tcg_single);

            break;



        case 3: /* float16 */

            tcg_single = tcg_temp_new_i32();

            if (is_signed) {

                gen_helper_vfp_sqtoh(tcg_single, tcg_int,

                                     tcg_shift, tcg_fpstatus);

            } else {

                gen_helper_vfp_uqtoh(tcg_single, tcg_int,

                                     tcg_shift, tcg_fpstatus);

            }

            write_fp_sreg(s, rd, tcg_single);

            tcg_temp_free_i32(tcg_single);

            break;



        default:

            g_assert_not_reached();

        }

    } else {

        TCGv_i64 tcg_int = cpu_reg(s, rd);
@@ -5571,8 +5591,9 @@ static void handle_fpfpcvt(DisasContext *s, int rd, int rn, int opcode, 


        gen_helper_set_rmode(tcg_rmode, tcg_rmode, tcg_fpstatus);



        if (is_double) {

            TCGv_i64 tcg_double = read_fp_dreg(s, rn);

        switch (type) {

        case 1: /* float64 */

            tcg_double = read_fp_dreg(s, rn);

            if (is_signed) {

                if (!sf) {

                    gen_helper_vfp_tosld(tcg_int, tcg_double,
@@ -5590,9 +5611,14 @@ static void handle_fpfpcvt(DisasContext *s, int rd, int rn, int opcode, 
                                         tcg_shift, tcg_fpstatus);

                }

            }

            if (!sf) {

                tcg_gen_ext32u_i64(tcg_int, tcg_int);

            }

            tcg_temp_free_i64(tcg_double);

        } else {

            TCGv_i32 tcg_single = read_fp_sreg(s, rn);

            break;



        case 0: /* float32 */

            tcg_single = read_fp_sreg(s, rn);

            if (sf) {

                if (is_signed) {

                    gen_helper_vfp_tosqs(tcg_int, tcg_single,
@@ -5614,14 +5640,39 @@ static void handle_fpfpcvt(DisasContext *s, int rd, int rn, int opcode, 
                tcg_temp_free_i32(tcg_dest);

            }

            tcg_temp_free_i32(tcg_single);

            break;



        case 3: /* float16 */

            tcg_single = read_fp_sreg(s, rn);

            if (sf) {

                if (is_signed) {

                    gen_helper_vfp_tosqh(tcg_int, tcg_single,

                                         tcg_shift, tcg_fpstatus);

                } else {

                    gen_helper_vfp_touqh(tcg_int, tcg_single,

                                         tcg_shift, tcg_fpstatus);

                }

            } else {

                TCGv_i32 tcg_dest = tcg_temp_new_i32();

                if (is_signed) {

                    gen_helper_vfp_toslh(tcg_dest, tcg_single,

                                         tcg_shift, tcg_fpstatus);

                } else {

                    gen_helper_vfp_toulh(tcg_dest, tcg_single,

                                         tcg_shift, tcg_fpstatus);

                }

                tcg_gen_extu_i32_i64(tcg_int, tcg_dest);

                tcg_temp_free_i32(tcg_dest);

            }

            tcg_temp_free_i32(tcg_single);

            break;



        default:

            g_assert_not_reached();

        }



        gen_helper_set_rmode(tcg_rmode, tcg_rmode, tcg_fpstatus);

        tcg_temp_free_i32(tcg_rmode);



        if (!sf) {

            tcg_gen_ext32u_i64(tcg_int, tcg_int);

        }

    }



    tcg_temp_free_ptr(tcg_fpstatus);
@@ -5791,7 +5842,20 @@ static void disas_fp_int_conv(DisasContext *s, uint32_t insn) 
        /* actual FP conversions */

        bool itof = extract32(opcode, 1, 1);



        if (type > 1 || (rmode != 0 && opcode > 1)) {

        if (rmode != 0 && opcode > 1) {

            unallocated_encoding(s);

            return;

        }

        switch (type) {

        case 0: /* float32 */

        case 1: /* float64 */

            break;

        case 3: /* float16 */

            if (arm_dc_feature(s, ARM_FEATURE_V8_FP16)) {

                break;

            }

            /* fallthru */

        default:

            unallocated_encoding(s);

            return;

        }