qemu-hppa floating point POWER function is incorrect

Host environment

• Operating system: Gentoo Linux
• OS/kernel version: Linux 5.10.52-gentoo #1 SMP Thu Aug 5 09:36:41 CEST 2021 x86_64 AMD Ryzen 5 3600 6-Core Processor AuthenticAMD GNU/Linux
• Architecture: AMD64
• QEMU flavor: qemu-hppa
• QEMU version: 6.0.0, also with git 6.1.50 version
• QEMU command line: qemu-hppa pow (the source provided)

Description of problem

The floating point power function produces incorrect values, and possibly stack misshapes as well.

Steps to reproduce

1. $ hppa1.1-unknown-linux-gnu-gcc pow.c -o pow -lm -static
2. $ qemu-hppa pow
3. the expected result is 10.0 ^ 6.0 = 6000000.0, instead of 403.45

Additional information

Example C source to reproduce, pow.c:

#include <stdio.h>
#include <math.h>
int main()
{
    double base, expo, res;
    base=10.0;
    expo=6.0;
    // res sould be 1e+6
    res = pow(base, expo);
    printf("%.1lf^%.1lf = %.2lf\n", base, expo, res);
    return 0;
}