diff options
Diffstat (limited to 'gitlab/issues/target_loongarch/host_missing/accel_missing/2865.toml')
| -rw-r--r-- | gitlab/issues/target_loongarch/host_missing/accel_missing/2865.toml | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/gitlab/issues/target_loongarch/host_missing/accel_missing/2865.toml b/gitlab/issues/target_loongarch/host_missing/accel_missing/2865.toml new file mode 100644 index 000000000..ed73610fb --- /dev/null +++ b/gitlab/issues/target_loongarch/host_missing/accel_missing/2865.toml @@ -0,0 +1,62 @@ +id = 2865 +title = "loongarch64: wrong implementation of `xvldi` instruction" +state = "closed" +created_at = "2025-03-16T17:39:40.541Z" +closed_at = "2025-03-17T12:59:28.649Z" +labels = ["target: loongarch"] +url = "https://gitlab.com/qemu-project/qemu/-/issues/2865" +host-os = "Debian" +host-arch = "loongarch64 (default one)" +qemu-version = "qemu-loongarch64 version 9.2.2 (Debian 1:9.2.2+ds-1+b2)" +guest-os = "n/a" +guest-arch = "loongarch64 (default one)" +description = """Consider this sample program. + +```c++ +#include <cstdio> +#include <cstdint> +#include <lsxintrin.h> +#include <lasxintrin.h> + +void dump_u32(__m256i x) { + uint32_t tmp[32/4]; + __lasx_xvst(x, tmp, 0); + putchar('['); + for (int i=0; i < 32/4; i++) { + if (i > 0) { + putchar(' '); + } + + printf("%08x", tmp[i]); + } + puts("]"); +} + +int main() { + __m256i const1 = __lasx_xvldi(-3832); + dump_u32(const1); +} +``` + +The magic constants here means: replicate in 32-bit words a byte (0x4) shifted left by 8. We should have a vector of words 0x800, and indeed, the program run on a real hardware prints expected: + +``` +[00000800 00000800 00000800 00000800 00000800 00000800 00000800 00000800] +``` + +The same program run under Qemu prints: + +``` +[08000800 00000000 08000800 00000000 08000800 00000000 08000800 00000000] +```""" +reproduce = "n/a" +additional = """I grabbed the latest sources, it seems there's bug in `target/loongarch/tcg/insn_trans/trans_vec.c.inc`, in function `vldi_get_value`. + +```c + case 1: + /* data: {2{16'0, imm[7:0], 8'0}} */ + data = (t << 24) | (t << 8); + break; +``` + +There should be `(t << (8+32)) | t << 8`.""" |