in kernel/fpu.c [21:83]
void save_fpu(struct task_struct *tsk)
{
unsigned int fpcfg, fpcsr;
enable_fpu();
fpcfg = ((__nds32__fmfcfg() & FPCFG_mskFREG) >> FPCFG_offFREG);
switch (fpcfg) {
case SP32_DP32_reg:
asm volatile ("fsdi $fd31, [%0+0xf8]\n\t"
"fsdi $fd30, [%0+0xf0]\n\t"
"fsdi $fd29, [%0+0xe8]\n\t"
"fsdi $fd28, [%0+0xe0]\n\t"
"fsdi $fd27, [%0+0xd8]\n\t"
"fsdi $fd26, [%0+0xd0]\n\t"
"fsdi $fd25, [%0+0xc8]\n\t"
"fsdi $fd24, [%0+0xc0]\n\t"
"fsdi $fd23, [%0+0xb8]\n\t"
"fsdi $fd22, [%0+0xb0]\n\t"
"fsdi $fd21, [%0+0xa8]\n\t"
"fsdi $fd20, [%0+0xa0]\n\t"
"fsdi $fd19, [%0+0x98]\n\t"
"fsdi $fd18, [%0+0x90]\n\t"
"fsdi $fd17, [%0+0x88]\n\t"
"fsdi $fd16, [%0+0x80]\n\t"
: /* no output */
: "r" (&tsk->thread.fpu)
: "memory");
fallthrough;
case SP32_DP16_reg:
asm volatile ("fsdi $fd15, [%0+0x78]\n\t"
"fsdi $fd14, [%0+0x70]\n\t"
"fsdi $fd13, [%0+0x68]\n\t"
"fsdi $fd12, [%0+0x60]\n\t"
"fsdi $fd11, [%0+0x58]\n\t"
"fsdi $fd10, [%0+0x50]\n\t"
"fsdi $fd9, [%0+0x48]\n\t"
"fsdi $fd8, [%0+0x40]\n\t"
: /* no output */
: "r" (&tsk->thread.fpu)
: "memory");
fallthrough;
case SP16_DP8_reg:
asm volatile ("fsdi $fd7, [%0+0x38]\n\t"
"fsdi $fd6, [%0+0x30]\n\t"
"fsdi $fd5, [%0+0x28]\n\t"
"fsdi $fd4, [%0+0x20]\n\t"
: /* no output */
: "r" (&tsk->thread.fpu)
: "memory");
fallthrough;
case SP8_DP4_reg:
asm volatile ("fsdi $fd3, [%1+0x18]\n\t"
"fsdi $fd2, [%1+0x10]\n\t"
"fsdi $fd1, [%1+0x8]\n\t"
"fsdi $fd0, [%1+0x0]\n\t"
"fmfcsr %0\n\t"
"swi %0, [%1+0x100]\n\t"
: "=&r" (fpcsr)
: "r"(&tsk->thread.fpu)
: "memory");
}
disable_fpu();
}