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[PULL 17/26] target/ppc: do not silence snan in xscvspdpn
From: |
Cédric Le Goater |
Subject: |
[PULL 17/26] target/ppc: do not silence snan in xscvspdpn |
Date: |
Tue, 4 Jan 2022 08:31:12 +0100 |
From: Matheus Ferst <matheus.ferst@eldorado.org.br>
The non-signalling versions of VSX scalar convert to shorter/longer
precision insns doesn't silence SNaNs in the hardware. To better match
this behavior, use the non-arithmatic conversion of helper_todouble
instead of float32_to_float64. A test is added to prevent future
regressions.
Signed-off-by: Matheus Ferst <matheus.ferst@eldorado.org.br>
Message-Id: <20211228120310.1957990-1-matheus.ferst@eldorado.org.br>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
---
target/ppc/fpu_helper.c | 5 +---
tests/tcg/ppc64le/non_signalling_xscv.c | 37 +++++++++++++++++++++++++
tests/tcg/ppc64/Makefile.target | 4 +--
tests/tcg/ppc64le/Makefile.target | 4 +--
4 files changed, 42 insertions(+), 8 deletions(-)
create mode 100644 tests/tcg/ppc64le/non_signalling_xscv.c
diff --git a/target/ppc/fpu_helper.c b/target/ppc/fpu_helper.c
index 700c79156b06..e5c29b53b8b5 100644
--- a/target/ppc/fpu_helper.c
+++ b/target/ppc/fpu_helper.c
@@ -2816,10 +2816,7 @@ uint64_t helper_xscvdpspn(CPUPPCState *env, uint64_t xb)
uint64_t helper_xscvspdpn(CPUPPCState *env, uint64_t xb)
{
- float_status tstat = env->fp_status;
- set_float_exception_flags(0, &tstat);
-
- return float32_to_float64(xb >> 32, &tstat);
+ return helper_todouble(xb >> 32);
}
/*
diff --git a/tests/tcg/ppc64le/non_signalling_xscv.c
b/tests/tcg/ppc64le/non_signalling_xscv.c
new file mode 100644
index 000000000000..91e25cad4681
--- /dev/null
+++ b/tests/tcg/ppc64le/non_signalling_xscv.c
@@ -0,0 +1,37 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <assert.h>
+
+#define TEST(INSN, B_HI, B_LO, T_HI, T_LO) \
+ do { \
+ uint64_t th, tl, bh = B_HI, bl = B_LO; \
+ asm("mtvsrd 0, %2\n\t" \
+ "mtvsrd 1, %3\n\t" \
+ "xxmrghd 0, 0, 1\n\t" \
+ INSN " 0, 0\n\t" \
+ "mfvsrd %0, 0\n\t" \
+ "xxswapd 0, 0\n\t" \
+ "mfvsrd %1, 0\n\t" \
+ : "=r" (th), "=r" (tl) \
+ : "r" (bh), "r" (bl) \
+ : "vs0", "vs1"); \
+ printf(INSN "(0x%016" PRIx64 "%016" PRIx64 ") = 0x%016" PRIx64 \
+ "%016" PRIx64 "\n", bh, bl, th, tl); \
+ assert(th == T_HI && tl == T_LO); \
+ } while (0)
+
+int main(void)
+{
+ /* SNaN shouldn't be silenced */
+ TEST("xscvspdpn", 0x7fbfffff00000000ULL, 0x0, 0x7ff7ffffe0000000ULL, 0x0);
+ TEST("xscvdpspn", 0x7ff7ffffffffffffULL, 0x0, 0x7fbfffff7fbfffffULL, 0x0);
+
+ /*
+ * SNaN inputs having no significant bits in the upper 23 bits of the
+ * signifcand will return Infinity as the result.
+ */
+ TEST("xscvdpspn", 0x7ff000001fffffffULL, 0x0, 0x7f8000007f800000ULL, 0x0);
+
+ return 0;
+}
diff --git a/tests/tcg/ppc64/Makefile.target b/tests/tcg/ppc64/Makefile.target
index 8f4c7ac4ed7d..0368007028c9 100644
--- a/tests/tcg/ppc64/Makefile.target
+++ b/tests/tcg/ppc64/Makefile.target
@@ -6,9 +6,9 @@ VPATH += $(SRC_PATH)/tests/tcg/ppc64
VPATH += $(SRC_PATH)/tests/tcg/ppc64le
ifneq ($(DOCKER_IMAGE)$(CROSS_CC_HAS_POWER8_VECTOR),)
-PPC64_TESTS=bcdsub
+PPC64_TESTS=bcdsub non_signalling_xscv
endif
-bcdsub: CFLAGS += -mpower8-vector
+$(PPC64_TESTS): CFLAGS += -mpower8-vector
PPC64_TESTS += byte_reverse
PPC64_TESTS += mtfsf
diff --git a/tests/tcg/ppc64le/Makefile.target
b/tests/tcg/ppc64le/Makefile.target
index e031f65adcb3..480ff0898d7e 100644
--- a/tests/tcg/ppc64le/Makefile.target
+++ b/tests/tcg/ppc64le/Makefile.target
@@ -5,9 +5,9 @@
VPATH += $(SRC_PATH)/tests/tcg/ppc64le
ifneq ($(DOCKER_IMAGE)$(CROSS_CC_HAS_POWER8_VECTOR),)
-PPC64LE_TESTS=bcdsub
+PPC64LE_TESTS=bcdsub non_signalling_xscv
endif
-bcdsub: CFLAGS += -mpower8-vector
+$(PPC64LE_TESTS): CFLAGS += -mpower8-vector
ifneq ($(DOCKER_IMAGE)$(CROSS_CC_HAS_POWER10),)
PPC64LE_TESTS += byte_reverse
--
2.31.1
- [PULL 00/26] ppc queue, Cédric Le Goater, 2022/01/04
- [PULL 04/26] pnv_phb3.c: do not set 'root-bus' as bus name, Cédric Le Goater, 2022/01/04
- [PULL 19/26] target/ppc: powerpc_excp: Add excp_vectors bounds check, Cédric Le Goater, 2022/01/04
- [PULL 24/26] target/ppc: Rewrite pmu_increment_insns, Cédric Le Goater, 2022/01/04
- [PULL 16/26] ppc/ppc405: Dump specific registers, Cédric Le Goater, 2022/01/04
- [PULL 07/26] target/ppc: Check effective address validity, Cédric Le Goater, 2022/01/04
- [PULL 21/26] target/ppc: powerpc_excp: Move system call vectored code together, Cédric Le Goater, 2022/01/04
- [PULL 17/26] target/ppc: do not silence snan in xscvspdpn,
Cédric Le Goater <=
- [PULL 14/26] ppc/ppc405: Fix timer initialization, Cédric Le Goater, 2022/01/04
- [PULL 20/26] target/ppc: powerpc_excp: Set vector earlier, Cédric Le Goater, 2022/01/04
- [PULL 11/26] ppc/ppc405: Activate MMU logs, Cédric Le Goater, 2022/01/04
- [PULL 05/26] pnv_phb4.c: do not set 'root-bus' as bus name, Cédric Le Goater, 2022/01/04
- [PULL 06/26] target/ppc: Improve logging in Radix MMU, Cédric Le Goater, 2022/01/04
- [PULL 13/26] ppc/ppc405: Rework ppc_40x_timers_init() to use a PowerPCCPU, Cédric Le Goater, 2022/01/04
- [PULL 12/26] ppc/ppc405: Restore TCR and STR write handlers, Cédric Le Goater, 2022/01/04
- [PULL 10/26] ppc/ppc4xx: Convert printfs(), Cédric Le Goater, 2022/01/04