[Qemu-devel] [PULL 037/118] target-ppc: Introduce DFP Test Data Group

[Alexander Graf <agraf@suse.de>]

From: Tom Musta <tommusta@gmail.com>

Add emulation of the PowerPC Decimal Floating Point Test Data
Group instructions dtstdg[q][.].

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
---
 target-ppc/dfp_helper.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++
 target-ppc/helper.h     |  2 ++
 target-ppc/translate.c  |  4 ++++
 3 files changed, 61 insertions(+)

diff --git a/target-ppc/dfp_helper.c b/target-ppc/dfp_helper.c
index fcd6fef..7f18fd9 100644
--- a/target-ppc/dfp_helper.c
+++ b/target-ppc/dfp_helper.c
@@ -449,3 +449,58 @@ uint32_t helper_##op(CPUPPCState *env, uint64_t *a, uint32_t dcm)        \
 
 DFP_HELPER_TSTDC(dtstdc, 64)
 DFP_HELPER_TSTDC(dtstdcq, 128)
+
+#define DFP_HELPER_TSTDG(op, size)                                       \
+uint32_t helper_##op(CPUPPCState *env, uint64_t *a, uint32_t dcm)        \
+{                                                                        \
+    struct PPC_DFP dfp;                                                  \
+    int minexp, maxexp, nzero_digits, nzero_idx, is_negative, is_zero,   \
+        is_extreme_exp, is_subnormal, is_normal, leftmost_is_nonzero,    \
+        match;                                                           \
+                                                                         \
+    dfp_prepare_decimal##size(&dfp, a, 0, env);                          \
+                                                                         \
+    if ((size) == 64) {                                                  \
+        minexp = -398;                                                   \
+        maxexp = 369;                                                    \
+        nzero_digits = 16;                                               \
+        nzero_idx = 5;                                                   \
+    } else if ((size) == 128) {                                          \
+        minexp = -6176;                                                  \
+        maxexp = 6111;                                                   \
+        nzero_digits = 34;                                               \
+        nzero_idx = 11;                                                  \
+    }                                                                    \
+                                                                         \
+    is_negative = decNumberIsNegative(&dfp.a);                           \
+    is_zero = decNumberIsZero(&dfp.a);                                   \
+    is_extreme_exp = (dfp.a.exponent == maxexp) ||                       \
+                     (dfp.a.exponent == minexp);                         \
+    is_subnormal = decNumberIsSubnormal(&dfp.a, &dfp.context);           \
+    is_normal = decNumberIsNormal(&dfp.a, &dfp.context);                 \
+    leftmost_is_nonzero = (dfp.a.digits == nzero_digits) &&              \
+                          (dfp.a.lsu[nzero_idx] != 0);                   \
+    match = 0;                                                           \
+                                                                         \
+    match |= (dcm & 0x20) && is_zero && !is_extreme_exp;                 \
+    match |= (dcm & 0x10) && is_zero && is_extreme_exp;                  \
+    match |= (dcm & 0x08) &&                                             \
+             (is_subnormal || (is_normal && is_extreme_exp));            \
+    match |= (dcm & 0x04) && is_normal && !is_extreme_exp &&             \
+             !leftmost_is_nonzero;                                       \
+    match |= (dcm & 0x02) && is_normal && !is_extreme_exp &&             \
+             leftmost_is_nonzero;                                        \
+    match |= (dcm & 0x01) && decNumberIsSpecial(&dfp.a);                 \
+                                                                         \
+    if (is_negative) {                                                   \
+        dfp.crbf = match ? 0xA : 0x8;                                    \
+    } else {                                                             \
+        dfp.crbf = match ? 0x2 : 0x0;                                    \
+    }                                                                    \
+                                                                         \
+    dfp_set_FPCC_from_CRBF(&dfp);                                        \
+    return dfp.crbf;                                                     \
+}
+
+DFP_HELPER_TSTDG(dtstdg, 64)
+DFP_HELPER_TSTDG(dtstdgq, 128)
diff --git a/target-ppc/helper.h b/target-ppc/helper.h
index 5a1e05e..dad4b87 100644
--- a/target-ppc/helper.h
+++ b/target-ppc/helper.h
@@ -630,3 +630,5 @@ DEF_HELPER_3(dcmpu, i32, env, fprp, fprp)
 DEF_HELPER_3(dcmpuq, i32, env, fprp, fprp)
 DEF_HELPER_3(dtstdc, i32, env, fprp, i32)
 DEF_HELPER_3(dtstdcq, i32, env, fprp, i32)
+DEF_HELPER_3(dtstdg, i32, env, fprp, i32)
+DEF_HELPER_3(dtstdgq, i32, env, fprp, i32)
diff --git a/target-ppc/translate.c b/target-ppc/translate.c
index 5dff96b..845d670 100644
--- a/target-ppc/translate.c
+++ b/target-ppc/translate.c
@@ -8369,6 +8369,8 @@ GEN_DFP_BF_A_B(dcmpo)
 GEN_DFP_BF_A_B(dcmpoq)
 GEN_DFP_BF_A_DCM(dtstdc)
 GEN_DFP_BF_A_DCM(dtstdcq)
+GEN_DFP_BF_A_DCM(dtstdg)
+GEN_DFP_BF_A_DCM(dtstdgq)
 /***                           SPE extension                               ***/
 /* Register moves */
 
@@ -11310,6 +11312,8 @@ GEN_DFP_BF_A_B(dcmpo, 0x02, 0x04),
 GEN_DFP_BF_Ap_Bp(dcmpoq, 0x02, 0x04),
 GEN_DFP_BF_A_DCM(dtstdc, 0x02, 0x06),
 GEN_DFP_BF_Ap_DCM(dtstdcq, 0x02, 0x06),
+GEN_DFP_BF_A_DCM(dtstdg, 0x02, 0x07),
+GEN_DFP_BF_Ap_DCM(dtstdgq, 0x02, 0x07),
 #undef GEN_SPE
 #define GEN_SPE(name0, name1, opc2, opc3, inval0, inval1, type) \
     GEN_OPCODE_DUAL(name0##_##name1, 0x04, opc2, opc3, inval0, inval1, type, PPC_NONE)
-- 
1.8.1.4