Re: [PATCH 3/3] tests/tcg/s390x: test signed vfmin/vfmax

[Richard Henderson]

On 7/12/22 07:27, Ilya Leoshkevich wrote:
> +/*
> + * vfmin/vfmax code generation.
> + */
> +extern const char vfminmax_template[];
> +extern const int vfminmax_template_size;
> +extern const int vfminmax_offset;
> +asm(".globl vfminmax_template\n"
> +    "vfminmax_template:\n"
> +    "vl %v25,0(%r3)\n"
> +    "vl %v26,0(%r4)\n"
> +    "0: vfmax %v24,%v25,%v26,2,0,0\n"
> +    "vst %v24,0(%r2)\n"
> +    "br %r14\n"
> +    "1: .align 4\n"
> +    ".globl vfminmax_template_size\n"
> +    "vfminmax_template_size: .long 1b - vfminmax_template\n"
> +    ".globl vfminmax_offset\n"
> +    "vfminmax_offset: .long 0b - vfminmax_template\n");
...
> +
> +#define VFMIN 0xEE
> +#define VFMAX 0xEF
> +
> +static void vfminmax(unsigned char *buf, unsigned int op,
> +                     unsigned int m4, unsigned int m5, unsigned int m6,
> +                     void *v1, const void *v2, const void *v3)
> +{
> +    memcpy(buf, vfminmax_template, vfminmax_template_size);
> +    buf[vfminmax_offset + 3] = (m6 << 4) | m5;
> +    buf[vfminmax_offset + 4] &= 0x0F;
> +    buf[vfminmax_offset + 4] |= (m4 << 4);
> +    buf[vfminmax_offset + 5] = op;
> +    ((void (*)(void *, const void *, const void *))buf)(v1, v2, v3);
> +}

This works, of course.  It could be simpler using EXECUTE, to store just the one 
instruction and not worry about an executable mapped page, but I guess it doesn't matter.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~