diff options
Diffstat (limited to 'gitlab/issues/target_missing/host_missing/accel_missing/2386.toml')
| -rw-r--r-- | gitlab/issues/target_missing/host_missing/accel_missing/2386.toml | 51 |
1 files changed, 0 insertions, 51 deletions
diff --git a/gitlab/issues/target_missing/host_missing/accel_missing/2386.toml b/gitlab/issues/target_missing/host_missing/accel_missing/2386.toml deleted file mode 100644 index 6805d773f..000000000 --- a/gitlab/issues/target_missing/host_missing/accel_missing/2386.toml +++ /dev/null @@ -1,51 +0,0 @@ -id = 2386 -title = "RISCV - Incorrect behaviour of the SLL instruction" -state = "closed" -created_at = "2024-06-09T18:31:27.404Z" -closed_at = "2024-06-09T18:38:34.624Z" -labels = ["Closed::Invalid"] -url = "https://gitlab.com/qemu-project/qemu/-/issues/2386" -host-os = "WSL2, Windows 10" -host-arch = "x86" -qemu-version = "qemu-riscv64 version 9.0.50 (v9.0.0-1377-g3e246da2c3)" -guest-os = "n/a" -guest-arch = "n/a" -description = """`SLL` (and probably other similar instructions) produce incorrect results. To quote the [RISCV ISA manual](https://drive.google.com/file/d/1uviu1nH-tScFfgrovvFCrj7Omv8tFtkp/view): - -> SLL, SRL, and SRA perform logical left, logical right, and arithmetic right shifts on the value in register -rs1 by the shift amount held in the lower 5 bits of register rs2. - -This instruction should perform a logical shift left by the shift amount from the lower 5 bits held in the third operand, however, it doesn't seem to be the case. As can be seen from the result of the snippet below: `55c3585000000000`, it seems that it calculates the correct value, but then shifts it by another 32 bits to the left: - -```python -correct_shift_res = (0xDB4D6868655C3585 << (0x69C99AB9B9401024 & 0b11111)) & (2 ** 64 - 1) -incorrect_qemu_produced = (correct_shift_res << 32) & (2 ** 64 - 1) -```""" -reproduce = """1. Compile the attached source file: `riscv64-linux-gnu-gcc -static repro.c -o ./repro.elf` - -```c -#include <stdint.h> -#include <stdio.h> - -int main() { - uint64_t a = 0x69C99AB9B9401024; - uint64_t b = 0xDB4D6868655C3585; - uint64_t c; - - asm volatile("sll %0, %1, %2" : "=r"(c) : "r"(b), "r"(a)); - - printf("s8 : %lx\\n", c); - printf("expected: %lx\\n", 0xb4d6868655c35850); - - return 0; -} -``` - -2. Run qemu: `./qemu-riscv64 ./repro.elf` -3. You will see the output and what the result of the computation should really be: - -``` -s8 : 55c3585000000000 -expected: b4d6868655c35850 -```""" -additional = """""" |