From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LsOFW-0004H4-C8 for qemu-devel@nongnu.org; Fri, 10 Apr 2009 17:26:58 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LsOFU-0004F5-L0 for qemu-devel@nongnu.org; Fri, 10 Apr 2009 17:26:57 -0400 Received: from [199.232.76.173] (port=34453 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LsOFU-0004Em-Ds for qemu-devel@nongnu.org; Fri, 10 Apr 2009 17:26:56 -0400 Received: from hall.aurel32.net ([88.191.82.174]:58450) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1LsOFT-00088d-T5 for qemu-devel@nongnu.org; Fri, 10 Apr 2009 17:26:56 -0400 Date: Fri, 10 Apr 2009 23:26:35 +0200 From: Aurelien Jarno Subject: Re: [Qemu-devel] [PATCH] Alpha bug fix: overflow condition for sublv and subqv Message-ID: <20090410212635.GA8217@volta.aurel32.net> References: <1239353720-67935-1-git-send-email-gingold@adacore.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <1239353720-67935-1-git-send-email-gingold@adacore.com> Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Tristan Gingold Cc: qemu-devel@nongnu.org On Fri, Apr 10, 2009 at 10:55:20AM +0200, Tristan Gingold wrote: > The conditions to detect overflow in sub operations was wrong. > > This patch is necessary to boot Tru64. > > Signed-off-by: Tristan Gingold > --- > 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 Thanks, applied. > 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 > > > > -- Aurelien Jarno GPG: 1024D/F1BCDB73 aurelien@aurel32.net http://www.aurel32.net