ARM FP16 support

Implement the ARM VFP half precision floating point extensions.

Signed-off-by: Paul Brook <paul@codesourcery.com>

4 files changed, 105 insertions, 0 deletions

diff --git a/target-arm/cpu.h b/target-arm/cpu.h
index 257e7aa70..6c0f9d61d 100644
--- a/target-arm/cpu.h
+++ b/target-arm/cpu.h
@@ -337,6 +337,7 @@ enum arm_features {
     ARM_FEATURE_THUMB2,
     ARM_FEATURE_MPU,    /* Only has Memory Protection Unit, not full MMU.  */
     ARM_FEATURE_VFP3,
+    ARM_FEATURE_VFP_FP16,
     ARM_FEATURE_NEON,
     ARM_FEATURE_DIV,
     ARM_FEATURE_M, /* Microcontroller profile.  */
diff --git a/target-arm/helper.c b/target-arm/helper.c
index 5e10533f1..cb95c6eab 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -115,6 +115,7 @@ static void cpu_reset_model_id(CPUARMState *env, uint32_t id)
         set_feature(env, ARM_FEATURE_THUMB2);
         set_feature(env, ARM_FEATURE_VFP);
         set_feature(env, ARM_FEATURE_VFP3);
+        set_feature(env, ARM_FEATURE_VFP_FP16);
         set_feature(env, ARM_FEATURE_NEON);
         set_feature(env, ARM_FEATURE_THUMB2EE);
         set_feature(env, ARM_FEATURE_DIV);
@@ -2568,6 +2569,21 @@ VFP_CONV_FIX(uh, s, float32, uint16, u)
 VFP_CONV_FIX(ul, s, float32, uint32, u)
 #undef VFP_CONV_FIX
 
+/* Half precision conversions.  */
+float32 HELPER(vfp_fcvt_f16_to_f32)(uint32_t a, CPUState *env)
+{
+    float_status *s = &env->vfp.fp_status;
+    int ieee = (env->vfp.xregs[ARM_VFP_FPSCR] & (1 << 26)) == 0;
+    return float16_to_float32(a, ieee, s);
+}
+
+uint32_t HELPER(vfp_fcvt_f32_to_f16)(float32 a, CPUState *env)
+{
+    float_status *s = &env->vfp.fp_status;
+    int ieee = (env->vfp.xregs[ARM_VFP_FPSCR] & (1 << 26)) == 0;
+    return float32_to_float16(a, ieee, s);
+}
+
 float32 HELPER(recps_f32)(float32 a, float32 b, CPUState *env)
 {
     float_status *s = &env->vfp.fp_status;
diff --git a/target-arm/helpers.h b/target-arm/helpers.h
index 4d07e0cea..dc25f185d 100644
--- a/target-arm/helpers.h
+++ b/target-arm/helpers.h
@@ -131,6 +131,9 @@ DEF_HELPER_3(vfp_sltod, f64, f64, i32, env)
 DEF_HELPER_3(vfp_uhtod, f64, f64, i32, env)
 DEF_HELPER_3(vfp_ultod, f64, f64, i32, env)
 
+DEF_HELPER_2(vfp_fcvt_f16_to_f32, f32, i32, env)
+DEF_HELPER_2(vfp_fcvt_f32_to_f16, i32, f32, env)
+
 DEF_HELPER_3(recps_f32, f32, f32, f32, env)
 DEF_HELPER_3(rsqrts_f32, f32, f32, f32, env)
 DEF_HELPER_2(recpe_f32, f32, f32, env)
diff --git a/target-arm/translate.c b/target-arm/translate.c
index 57845662a..a002f7e02 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -2974,6 +2974,47 @@ static int disas_vfp_insn(CPUState * env, DisasContext *s, uint32_t insn)
                     case 3: /* sqrt */
                         gen_vfp_sqrt(dp);
                         break;
+                    case 4: /* vcvtb.f32.f16 */
+                        if (!arm_feature(env, ARM_FEATURE_VFP_FP16))
+                          return 1;
+                        tmp = gen_vfp_mrs();
+                        tcg_gen_ext16u_i32(tmp, tmp);
+                        gen_helper_vfp_fcvt_f16_to_f32(cpu_F0s, tmp, cpu_env);
+                        dead_tmp(tmp);
+                        break;
+                    case 5: /* vcvtt.f32.f16 */
+                        if (!arm_feature(env, ARM_FEATURE_VFP_FP16))
+                          return 1;
+                        tmp = gen_vfp_mrs();
+                        tcg_gen_shri_i32(tmp, tmp, 16);
+                        gen_helper_vfp_fcvt_f16_to_f32(cpu_F0s, tmp, cpu_env);
+                        dead_tmp(tmp);
+                        break;
+                    case 6: /* vcvtb.f16.f32 */
+                        if (!arm_feature(env, ARM_FEATURE_VFP_FP16))
+                          return 1;
+                        tmp = new_tmp();
+                        gen_helper_vfp_fcvt_f32_to_f16(tmp, cpu_F0s, cpu_env);
+                        gen_mov_F0_vreg(0, rd);
+                        tmp2 = gen_vfp_mrs();
+                        tcg_gen_andi_i32(tmp2, tmp2, 0xffff0000);
+                        tcg_gen_or_i32(tmp, tmp, tmp2);
+                        dead_tmp(tmp2);
+                        gen_vfp_msr(tmp);
+                        break;
+                    case 7: /* vcvtt.f16.f32 */
+                        if (!arm_feature(env, ARM_FEATURE_VFP_FP16))
+                          return 1;
+                        tmp = new_tmp();
+                        gen_helper_vfp_fcvt_f32_to_f16(tmp, cpu_F0s, cpu_env);
+                        tcg_gen_shli_i32(tmp, tmp, 16);
+                        gen_mov_F0_vreg(0, rd);
+                        tmp2 = gen_vfp_mrs();
+                        tcg_gen_ext16u_i32(tmp2, tmp2);
+                        tcg_gen_or_i32(tmp, tmp, tmp2);
+                        dead_tmp(tmp2);
+                        gen_vfp_msr(tmp);
+                        break;
                     case 8: /* cmp */
                         gen_vfp_cmp(dp);
                         break;
@@ -5328,6 +5369,50 @@ static int disas_neon_data_insn(CPUState * env, DisasContext *s, uint32_t insn)
                         neon_store_reg64(cpu_V0, rd + pass);
                     }
                     break;
+                case 44: /* VCVT.F16.F32 */
+                    if (!arm_feature(env, ARM_FEATURE_VFP_FP16))
+                      return 1;
+                    tmp = new_tmp();
+                    tmp2 = new_tmp();
+                    tcg_gen_ld_f32(cpu_F0s, cpu_env, neon_reg_offset(rm, 0));
+                    gen_helper_vfp_fcvt_f32_to_f16(tmp, cpu_F0s, cpu_env);
+                    tcg_gen_ld_f32(cpu_F0s, cpu_env, neon_reg_offset(rm, 1));
+                    gen_helper_vfp_fcvt_f32_to_f16(tmp2, cpu_F0s, cpu_env);
+                    tcg_gen_shli_i32(tmp2, tmp2, 16);
+                    tcg_gen_or_i32(tmp2, tmp2, tmp);
+                    tcg_gen_ld_f32(cpu_F0s, cpu_env, neon_reg_offset(rm, 2));
+                    gen_helper_vfp_fcvt_f32_to_f16(tmp, cpu_F0s, cpu_env);
+                    tcg_gen_ld_f32(cpu_F0s, cpu_env, neon_reg_offset(rm, 3));
+                    neon_store_reg(rd, 0, tmp2);
+                    tmp2 = new_tmp();
+                    gen_helper_vfp_fcvt_f32_to_f16(tmp2, cpu_F0s, cpu_env);
+                    tcg_gen_shli_i32(tmp2, tmp2, 16);
+                    tcg_gen_or_i32(tmp2, tmp2, tmp);
+                    neon_store_reg(rd, 1, tmp2);
+                    dead_tmp(tmp);
+                    break;
+                case 46: /* VCVT.F32.F16 */
+                    if (!arm_feature(env, ARM_FEATURE_VFP_FP16))
+                      return 1;
+                    tmp3 = new_tmp();
+                    tmp = neon_load_reg(rm, 0);
+                    tmp2 = neon_load_reg(rm, 1);
+                    tcg_gen_ext16u_i32(tmp3, tmp);
+                    gen_helper_vfp_fcvt_f16_to_f32(cpu_F0s, tmp3, cpu_env);
+                    tcg_gen_st_f32(cpu_F0s, cpu_env, neon_reg_offset(rd, 0));
+                    tcg_gen_shri_i32(tmp3, tmp, 16);
+                    gen_helper_vfp_fcvt_f16_to_f32(cpu_F0s, tmp3, cpu_env);
+                    tcg_gen_st_f32(cpu_F0s, cpu_env, neon_reg_offset(rd, 1));
+                    dead_tmp(tmp);
+                    tcg_gen_ext16u_i32(tmp3, tmp2);
+                    gen_helper_vfp_fcvt_f16_to_f32(cpu_F0s, tmp3, cpu_env);
+                    tcg_gen_st_f32(cpu_F0s, cpu_env, neon_reg_offset(rd, 2));
+                    tcg_gen_shri_i32(tmp3, tmp2, 16);
+                    gen_helper_vfp_fcvt_f16_to_f32(cpu_F0s, tmp3, cpu_env);
+                    tcg_gen_st_f32(cpu_F0s, cpu_env, neon_reg_offset(rd, 3));
+                    dead_tmp(tmp2);
+                    dead_tmp(tmp3);
+                    break;
                 default:
                 elementwise:
                     for (pass = 0; pass < (q ? 4 : 2); pass++) {