[Qemu-devel] [PATCH 16/18] target-ppc: Add ISA 2.06 ftsqrt

[Tom Musta <tommusta@gmail.com>]

This patch adds the Floating Point Test for Square Root instruction
which was introduced in Power ISA 2.06.

Signed-off-by: Tom Musta <tommusta@gmail.com>
---
 target-ppc/fpu_helper.c |   31 +++++++++++++++++++++++++++++++
 target-ppc/helper.h     |    1 +
 target-ppc/translate.c  |   14 ++++++++++++++
 3 files changed, 46 insertions(+), 0 deletions(-)

diff --git a/target-ppc/fpu_helper.c b/target-ppc/fpu_helper.c
index 4977618..74f43fa 100644
--- a/target-ppc/fpu_helper.c
+++ b/target-ppc/fpu_helper.c
@@ -1034,6 +1034,37 @@ void helper_ftdiv(CPUPPCState *env, uint32_t bf, uint64_t fra, uint64_t frb)
     env->crf[bf] = 0x8 | (fg_flag ? 4 : 0) | (fe_flag ? 2 : 0);
 }
 
+void helper_ftsqrt(CPUPPCState *env, uint32_t bf, uint64_t frb)
+{
+    int fe_flag = 0;
+    int fg_flag = 0;
+
+    if (unlikely(float64_is_infinity(frb) || float64_is_zero(frb))) {
+        fe_flag = 1;
+        fg_flag = 1;
+    } else {
+        int e_b = ppc_float64_get_unbiased_exp(frb);
+
+        if (unlikely(float64_is_any_nan(frb))) {
+            fe_flag = 1;
+        } else if (unlikely(float64_is_zero(frb))) {
+            fe_flag = 1;
+        } else if (unlikely(float64_is_neg(frb))) {
+            fe_flag = 1;
+        } else if (!float64_is_zero(frb) && (e_b <= (-1022+52))) {
+            fe_flag = 1;
+        }
+
+        if (unlikely(float64_is_zero_or_denormal(frb))) {
+            /* XB is not zero because of the above check and */
+            /* therefore must be denormalized.               */
+            fg_flag = 1;
+        }
+    }
+
+    env->crf[bf] = 0x8 | (fg_flag ? 4 : 0) | (fe_flag ? 2 : 0);
+}
+
 void helper_fcmpu(CPUPPCState *env, uint64_t arg1, uint64_t arg2,
                   uint32_t crfD)
 {
diff --git a/target-ppc/helper.h b/target-ppc/helper.h
index 5f5d3f6..ccf5711 100644
--- a/target-ppc/helper.h
+++ b/target-ppc/helper.h
@@ -98,6 +98,7 @@ DEF_HELPER_2(frsqrte, i64, env, i64)
 DEF_HELPER_4(fsel, i64, env, i64, i64, i64)
 
 DEF_HELPER_4(ftdiv, void, env, i32, i64, i64)
+DEF_HELPER_3(ftsqrt, void, env, i32, i64)
 
 #define dh_alias_avr ptr
 #define dh_ctype_avr ppc_avr_t *
diff --git a/target-ppc/translate.c b/target-ppc/translate.c
index 2362c12..eb1c49a 100644
--- a/target-ppc/translate.c
+++ b/target-ppc/translate.c
@@ -2317,6 +2317,19 @@ static void gen_ftdiv(DisasContext *ctx)
                      cpu_fpr[rB(ctx->opcode)]);
 }
 
+static void gen_ftsqrt(DisasContext *ctx)
+{
+    TCGv_i32 bf;
+    if (unlikely(!ctx->fpu_enabled)) {
+        gen_exception(ctx, POWERPC_EXCP_FPU);
+        return;
+    }
+    /* NIP cannot be restored if the memory exception comes from an helper */
+    gen_update_nip(ctx, ctx->nip - 4);
+    bf = tcg_const_i32(crfD(ctx->opcode));
+    gen_helper_ftsqrt(cpu_env, bf, cpu_fpr[rB(ctx->opcode)]);
+}
+
 
 
 /***                         Floating-Point compare                        ***/
@@ -9823,6 +9836,7 @@ GEN_FLOAT_ACB(msub, 0x1C, 1, PPC_FLOAT),
 GEN_FLOAT_ACB(nmadd, 0x1F, 1, PPC_FLOAT),
 GEN_FLOAT_ACB(nmsub, 0x1E, 1, PPC_FLOAT),
 GEN_HANDLER_E(ftdiv, 0x3F, 0x00, 0x04, 1, PPC_NONE, PPC2_ISA206),
+GEN_HANDLER_E(ftsqrt, 0x3F, 0x00, 0x05, 1, PPC_NONE, PPC2_ISA206),
 GEN_FLOAT_B(ctiw, 0x0E, 0x00, 0, PPC_FLOAT),
 GEN_HANDLER_E(fctiwu, 0x3F, 0x0E, 0x04, 0x00000000, PPC_NONE, PPC2_ISA206),
 GEN_FLOAT_B(ctiwz, 0x0F, 0x00, 0, PPC_FLOAT),
-- 
1.7.1