64 bit System API

[nexos]

Hello,
I am working on a 64 bit system API dispatcher, but the function throws an invalid opcode when called. Here is the function

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VOID SchedApiDispatch(REGS* r)
{
    if(r->rax > MAXSYSCALL)
    {
        r->rax = 0;
        return;
    }
    VOID* location = syscalls[r->rax];
    QWORD ret = 0;
    asm volatile (" \
        mov %1, %%rdi; \
        mov %2, %%rsi; \
        mov %3, %%rdx; \
        mov %4, %%rcx; \
        mov %5, %%r8; \
        mov %6, %%r9; \
        call *%7; \
        add $48, %%esp; \
        " : "=a" (ret) : "r" (r->rdi), "r" (r->rsi), "r" (r->rdx), "r" (r->rcx), "r" (r->r8), "r" (r->r9), "r" (location));
   r->rax = ret;
}

I have read through the ABI as well.
Thanks for your help,
nexos

[nexos]

I found the problem (perhaps maybe I should have debugged before posting ) I needed to use the m rather then the r constraint for the function address. It works now!

[Octocontrabass]

Couldn't you replace the inline assembly with something like this?

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return syscalls[r->rax](r);

[nexos]

Yes, I could! Thanks for the tip.