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Diffstat (limited to 'gitlab/issues/target_riscv/host_missing/accel_TCG/2371.toml')
| -rw-r--r-- | gitlab/issues/target_riscv/host_missing/accel_TCG/2371.toml | 60 |
1 files changed, 0 insertions, 60 deletions
diff --git a/gitlab/issues/target_riscv/host_missing/accel_TCG/2371.toml b/gitlab/issues/target_riscv/host_missing/accel_TCG/2371.toml deleted file mode 100644 index 0b6a10c6..00000000 --- a/gitlab/issues/target_riscv/host_missing/accel_TCG/2371.toml +++ /dev/null @@ -1,60 +0,0 @@ -id = 2371 -title = "A bug in RISC-V froundnx.h instruction" -state = "closed" -created_at = "2024-06-02T05:26:42.308Z" -closed_at = "2024-08-01T08:38:08.083Z" -labels = ["Closed::Fixed", "accel: TCG", "kind::Bug", "target: riscv"] -url = "https://gitlab.com/qemu-project/qemu/-/issues/2371" -host-os = "Ubuntu 22.04" -host-arch = "x86-64" -qemu-version = "qemu-riscv64 version 9.0.50 (v9.0.0-1123-g74abb45dac)" -guest-os = "N/A (qemu-user)" -guest-arch = "riscv64" -description = """According to the RISCV ISA manual, the froundnx.h instruction rounds a half-precision floating-point number in the source register to an integer and writes the integer, represented as a half-precision floating-point number, to the destination register. Because the values are stored in 64-bit width registers, they must be NaN-unboxed/boxed before/after the operation. When an input value lacks the proper form of NaN-boxing, it should be treated as a canonical NaN. -However, when an incorrectly NaN-boxed value is passed to froundnx.h, QEMU produces 0 instead of the canonical NaN. This is because there is a typo in the definition of helper_froundnx_h: -``` -// target/riscv/fpu_helper.c -uint64_t helper_froundnx_h(CPURISCVState *env, uint64_t rs1) -{ - float16 frs1 = check_nanbox_s(env, rs1); // This should be check_nanbox_h. - frs1 = float16_round_to_int(frs1, &env->fp_status); - return nanbox_h(env, frs1); -} -```""" -reproduce = """1. Write `test.c`. -``` -#include <stdio.h> - -char i_F6[8] = { 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 }; -char o_F5[8]; - -void __attribute__ ((noinline)) show_state() { - for (int i = 0; i < 8; i++) { - printf("%02x ", o_F5[i]); - } - printf("\\n"); -} - -void __attribute__ ((noinline)) run() { - __asm__ ( - "lui t5, %hi(i_F6)\\n" - "addi t5, t5, %lo(i_F6)\\n" - "fld ft6, 0(t5)\\n" - ".insn 0x445372d3\\n" // froundnx.h ft5, ft6 - "lui t5, %hi(o_F5)\\n" - "addi t5, t5, %lo(o_F5)\\n" - "fsd ft5, 0(t5)\\n" - ); -} - -int main(int argc, char **argv) { - run(); - show_state(); - - return 0; -} -``` -2. Compile `test.bin` using this command: `riscv64-linux-gnu-gcc-12 -O2 -no-pie -march=rv64iv ./test.c -o ./test.bin`. -3. Run QEMU using this command: `qemu-riscv64 -L /usr/riscv64-linux-gnu/ ./test.bin`. -4. The program, runs on top of the buggy QEMU, prints `00 00 ff ff ff ff ff ff`. It should print `00 7e ff ff ff ff ff ff` after the bug is fixed.""" -additional = """""" |