Re: [PATCH] target/i386: Fix 32-bit AD[CO]X insns in 64-bit mode

[Richard Henderson <richard.henderson@linaro.org>]

Ping.

Paolo, I see you've queued a fix for a different ADCOX bug in your latest pull.  You could 
probably adjust your new test for this case, but this problem is exclusively x86_64.

r~


On 1/14/23 15:21, Richard Henderson wrote:
> Failure to truncate the inputs results in garbage for the carry-out.
> 
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1373
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   tests/tcg/x86_64/adox.c          | 69 ++++++++++++++++++++++++++++++++
>   target/i386/tcg/emit.c.inc       |  2 +
>   tests/tcg/x86_64/Makefile.target |  3 ++
>   3 files changed, 74 insertions(+)
>   create mode 100644 tests/tcg/x86_64/adox.c
> 
> diff --git a/tests/tcg/x86_64/adox.c b/tests/tcg/x86_64/adox.c
> new file mode 100644
> index 0000000000..36be644c8b
> --- /dev/null
> +++ b/tests/tcg/x86_64/adox.c
> @@ -0,0 +1,69 @@
> +/* See if ADOX give expected results */
> +
> +#include <assert.h>
> +#include <stdint.h>
> +#include <stdbool.h>
> +
> +static uint64_t adoxq(bool *c_out, uint64_t a, uint64_t b, bool c)
> +{
> +    asm ("addl $0x7fffffff, %k1\n\t"
> +         "adoxq %2, %0\n\t"
> +         "seto %b1"
> +         : "+r"(a), "=&r"(c) : "r"(b), "1"((int)c));
> +    *c_out = c;
> +    return a;
> +}
> +
> +static uint64_t adoxl(bool *c_out, uint64_t a, uint64_t b, bool c)
> +{
> +    asm ("addl $0x7fffffff, %k1\n\t"
> +         "adoxl %k2, %k0\n\t"
> +         "seto %b1"
> +         : "+r"(a), "=&r"(c) : "r"(b), "1"((int)c));
> +    *c_out = c;
> +    return a;
> +}
> +
> +int main()
> +{
> +    uint64_t r;
> +    bool c;
> +
> +    r = adoxq(&c, 0, 0, 0);
> +    assert(r == 0);
> +    assert(c == 0);
> +
> +    r = adoxl(&c, 0, 0, 0);
> +    assert(r == 0);
> +    assert(c == 0);
> +
> +    r = adoxl(&c, 0x100000000, 0, 0);
> +    assert(r == 0);
> +    assert(c == 0);
> +
> +    r = adoxq(&c, 0, 0, 1);
> +    assert(r == 1);
> +    assert(c == 0);
> +
> +    r = adoxl(&c, 0, 0, 1);
> +    assert(r == 1);
> +    assert(c == 0);
> +
> +    r = adoxq(&c, -1, -1, 0);
> +    assert(r == -2);
> +    assert(c == 1);
> +
> +    r = adoxl(&c, -1, -1, 0);
> +    assert(r == 0xfffffffe);
> +    assert(c == 1);
> +
> +    r = adoxq(&c, -1, -1, 1);
> +    assert(r == -1);
> +    assert(c == 1);
> +
> +    r = adoxl(&c, -1, -1, 1);
> +    assert(r == 0xffffffff);
> +    assert(c == 1);
> +
> +    return 0;
> +}
> diff --git a/target/i386/tcg/emit.c.inc b/target/i386/tcg/emit.c.inc
> index 1eace1231a..d44c51209d 100644
> --- a/target/i386/tcg/emit.c.inc
> +++ b/target/i386/tcg/emit.c.inc
> @@ -1042,6 +1042,8 @@ static void gen_ADCOX(DisasContext *s, CPUX86State *env, MemOp ot, int cc_op)
>   #ifdef TARGET_X86_64
>       case MO_32:
>           /* If TL is 64-bit just do everything in 64-bit arithmetic.  */
> +        tcg_gen_ext32u_tl(s->T0, s->T0);
> +        tcg_gen_ext32u_tl(s->T1, s->T1);
>           tcg_gen_add_i64(s->T0, s->T0, s->T1);
>           tcg_gen_add_i64(s->T0, s->T0, carry_in);
>           tcg_gen_shri_i64(carry_out, s->T0, 32);
> diff --git a/tests/tcg/x86_64/Makefile.target b/tests/tcg/x86_64/Makefile.target
> index 4eac78293f..e64aab1b81 100644
> --- a/tests/tcg/x86_64/Makefile.target
> +++ b/tests/tcg/x86_64/Makefile.target
> @@ -12,11 +12,14 @@ ifeq ($(filter %-linux-user, $(TARGET)),$(TARGET))
>   X86_64_TESTS += vsyscall
>   X86_64_TESTS += noexec
>   X86_64_TESTS += cmpxchg
> +X86_64_TESTS += adox
>   TESTS=$(MULTIARCH_TESTS) $(X86_64_TESTS) test-x86_64
>   else
>   TESTS=$(MULTIARCH_TESTS)
>   endif
>   
> +adox: CFLAGS=-O2
> +
>   run-test-i386-ssse3: QEMU_OPTS += -cpu max
>   run-plugin-test-i386-ssse3-%: QEMU_OPTS += -cpu max
>