I am running xv6 via QEMU on Ubuntu 20.04.6 via Windows WSL. I wanted to write a syscall to extract and print the CPU vendor name by editing the kernel code. Did the usual pleasantries, wrote up a function that was successfully implemented as a syscall within xv6

I then edited the function to print the CPU vendor name, only to get the most perplexing of results

// within sysproc.c
#include "types.h"
#include "x86.h"
#include "defs.h"
#include "proc.h"

int sys_cpuvendor(void) 
{
    char *buf;
    if(argptr(0, &buf, 13) < 0) //take a 13 element buffer to write the results into
        return -1;

    unsigned int ebx, ecx, edx;
    asm volatile (
        "mov $0, %%eax; n"
        "cpuid; n"
        "mov %%ebx, %0; n"
        "mov %%edx, %1; n"
        "mov %%ecx, %2; n"
        : "=r"(ebx), "=r"(edx), "=r"(ecx)
        :
        : "%eax"
    );

//run cpuid via asm magic and write the results into registers, and finally into buf

    ((unsigned int*)buf)[0] = ebx;
    ((unsigned int*)buf)[1] = edx;
    ((unsigned int*)buf)[2] = ecx;
    buf[12] = ''; 

    return 0;
}

Here is the program that uses the syscall

int main(void) 
{


    char vendBuf[255];
    printf(1, "Printing device info with deviceInfo() call: ");
    deviceInfo(vendBuf);
    printf(1, "CPU Vendor Name: %sn", vendBuf);
    exit();
 }

Running this function and printing the buffer it writes to gives me a strange result. The output is Genuntelntel, with the typo. The funny part is I am working on an AMD Ryzen machine? How and why did it get the CPU vendor wrong entirely, let alone the typo?