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[Qemu-devel] [PATCH] Alpha bug fix: overflow condition for sublv and sub
From: |
Tristan Gingold |
Subject: |
[Qemu-devel] [PATCH] Alpha bug fix: overflow condition for sublv and subqv |
Date: |
Fri, 10 Apr 2009 10:55:20 +0200 |
The conditions to detect overflow in sub operations was wrong.
This patch is necessary to boot Tru64.
Signed-off-by: Tristan Gingold <address@hidden>
---
target-alpha/op_helper.c | 20 ++++++++++----------
tests/alpha/Makefile | 3 +++
tests/alpha/test-ovf.c | 29 +++++++++++++++++++++++++++++
3 files changed, 42 insertions(+), 10 deletions(-)
create mode 100644 tests/alpha/test-ovf.c
diff --git a/target-alpha/op_helper.c b/target-alpha/op_helper.c
index 7ad1b3d..3c95e98 100644
--- a/target-alpha/op_helper.c
+++ b/target-alpha/op_helper.c
@@ -158,22 +158,22 @@ uint64_t helper_addlv (uint64_t op1, uint64_t op2)
uint64_t helper_subqv (uint64_t op1, uint64_t op2)
{
- uint64_t tmp = op1;
- op1 -= op2;
- if (unlikely(((~tmp) ^ op1 ^ (-1ULL)) & ((~tmp) ^ op2) & (1ULL << 63))) {
- helper_excp(EXCP_ARITH, EXCP_ARITH_OVERFLOW);
+ uint64_t res;
+ res = op1 - op2;
+ if (unlikely((op1 ^ op2) & (res ^ op1) & (1ULL << 63))) {
+ helper_excp(EXCP_GEN_ARITH, EXCP_ARITH_OVERFLOW);
}
- return op1;
+ return res;
}
uint64_t helper_sublv (uint64_t op1, uint64_t op2)
{
- uint64_t tmp = op1;
- op1 = (uint32_t)(op1 - op2);
- if (unlikely(((~tmp) ^ op1 ^ (-1UL)) & ((~tmp) ^ op2) & (1UL << 31))) {
- helper_excp(EXCP_ARITH, EXCP_ARITH_OVERFLOW);
+ uint32_t res;
+ res = op1 - op2;
+ if (unlikely((op1 ^ op2) & (res ^ op1) & (1UL << 31))) {
+ helper_excp(EXCP_GEN_ARITH, EXCP_ARITH_OVERFLOW);
}
- return op1;
+ return res;
}
uint64_t helper_mullv (uint64_t op1, uint64_t op2)
diff --git a/tests/alpha/Makefile b/tests/alpha/Makefile
index e4e23d2..2b1f03d 100644
--- a/tests/alpha/Makefile
+++ b/tests/alpha/Makefile
@@ -23,6 +23,9 @@ test-cmov.o: test-cond.c
test-cmov: test-cmov.o crt.o
$(LINK)
+test-ovf: test-ovf.o crt.o
+ $(LINK)
+
check: $(TESTS)
for f in $(TESTS); do $(SIM) $$f || exit 1; done
diff --git a/tests/alpha/test-ovf.c b/tests/alpha/test-ovf.c
new file mode 100644
index 0000000..01c80e7
--- /dev/null
+++ b/tests/alpha/test-ovf.c
@@ -0,0 +1,29 @@
+static long test_subqv (long a, long b)
+{
+ long res;
+
+ asm ("subq/v %1,%2,%0"
+ : "=r" (res) : "r" (a), "r" (b));
+ return res;
+}
+static struct {
+ long (*func)(long, long);
+ long a;
+ long b;
+ long r;
+} vectors[] =
+ {
+ {test_subqv, 0, 0x7d54000, 0xfffffffff82ac000L}
+ };
+
+int main (void)
+{
+ int i;
+
+ for (i = 0; i < sizeof (vectors)/sizeof(vectors[0]); i++)
+ if ((*vectors[i].func)(vectors[i].a, vectors[i].b) != vectors[i].r) {
+ write(1, "Failed\n", 7);
+ }
+ write(1, "OK\n", 3);
+ return 0;
+}
--
1.6.2
- [Qemu-devel] [PATCH] Alpha bug fix: overflow condition for sublv and subqv,
Tristan Gingold <=