相关疑难解决方法(0)

在尝试使用内在函数和汇编来回答嵌入式广播时,我试图做这样的事情:

__m512 mul_broad(__m512 a, float b) {
    int scratch = 0;
    asm(
        "vbroadcastss  %k[scalar], %q[scalar]\n\t"  // want  vbr..  %xmm0, %zmm0
        "vmulps        %q[scalar], %[vec], %[vec]\n\t"

        // how it's done for integer registers
        "movw         symbol(%q[inttmp]), %w[inttmp]\n\t"  // movw symbol(%rax), %ax
        "movsbl        %h[inttmp], %k[inttmp]\n\t"  // movsx %ah, %eax
        : [vec] "+x" (a), [scalar] "+x" (b),  [inttmp] "=r" (scratch)
        :
        :
    );
    return a;
}

的GNU C 86操作数修饰符文档仅指定到改性剂q(DI(DoubleInt)尺寸,64位).使用q一个向量寄存器总会带给它归结为xmm(从ymm或zmm). …

在使用GCC的内联汇编程序功能时,我尝试创建一个立即退出该过程的函数,类似于_ExitC标准库.

以下是相关的源代码:

void immediate_exit(int code)
{
#if defined(__x86_64__)
    asm (
            //Load exit code into %rdi
            "mov %0, %%rdi\n\t"
            //Load system call number (group_exit)
            "mov $231, %%rax\n\t"
            //Linux syscall, 64-bit version.
            "syscall\n\t"
            //No output operands, single unrestricted input register, no clobbered registers because we're about to exit.
            :: "" (code) :
    );
//Skip other architectures here, I'll fix these later.
#else
#   error "Architecture not supported."
#endif
}

这适用于调试版本(带-O0),但只要我在任何级别打开优化,我都会收到以下错误:

immediate_exit.c: Assembler messages:
immediate_exit.c:4: Error: unsupported for `mov' …