From 5aa276efcbd67f4300ca1a7f809c6e00aadb03da Mon Sep 17 00:00:00 2001 From: Christian Krinitsin Date: Tue, 8 Jul 2025 13:28:15 +0200 Subject: restructure results --- .../zero-shot-user-mode/instruction/1821444 | 35 ++++++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 results/classifier/zero-shot-user-mode/instruction/1821444 (limited to 'results/classifier/zero-shot-user-mode/instruction/1821444') diff --git a/results/classifier/zero-shot-user-mode/instruction/1821444 b/results/classifier/zero-shot-user-mode/instruction/1821444 new file mode 100644 index 00000000..0f8cb900 --- /dev/null +++ b/results/classifier/zero-shot-user-mode/instruction/1821444 @@ -0,0 +1,35 @@ +instruction: 0.711 +runtime: 0.199 +syscall: 0.090 + + + +qemu-ppc (user) incorrectly translates float32 arithmetics + +I'm using qemu-3.1.0 (Gentoo). + +When I was running regression test suite via qemu-ppc for GHC I noticed a few uint32_t<->float32 failures I did not expect to encounter. + +Here is an example + +$ cat a.c +#include +#include + +int main() { + volatile uint32_t i = 1; + printf("0x1 = %e\n", *(volatile float*)&i); +} + +$ powerpc-unknown-linux-gnu-gcc -O2 a.c -Wall -o a -fno-strict-aliasing -fno-stack-protector -static && ./a +0x1 = 2.802597e-45 + +$ scp a timberdoodle.ppc64.dev.gentoo.org:~/ +a 100% 826KB 102.0KB/s 00:08 + +$ ssh timberdoodle.ppc64.dev.gentoo.org ./a +0x1 = 1.401298e-45 +$ qemu-ppc ./a +0x1 = 2.802597e-45 + +Looks like off-by-one bit somewhere. I'm not sure if it's FPU instruction or some internals of printf() that are emulated incorrectly. \ No newline at end of file -- cgit v1.2.3