arch/x86_64/sse.s


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.global enable_fpu
.type enable_fpu @function
enable_fpu:
    fninit
    fldcw [fcw_init]
    ret
.size enable_fpu, . - enable_fpu

.global enable_sse
.type enable_sse @function
enable_sse:
    movq %cr0, %rax
    //Disable coprocessor emulation
    and $0xFFFB, %ax
    //Set coprocessor monitoring
    or $0x22, %ax
    //Save cr0
    movq %rax, %cr0
    movq %cr4, %rax
    //Set CR4.OSFXR and CR4.OSXMMEXCEPT
    or $3 << 9, %ax
    movq %rax, %cr4
    ret
.size enable_sse, . - enable_sse

.global enable_avx
.type enable_avx, @function
enable_avx:
    pushq %rax
    pushq %rcx
    pushq %rdx

    xorq %rcx, %rcx
    xgetbv
    or $7, %eax
    xsetbv

    popq %rdx
    popq %rcx
    popq %rax
    ret
.size enable_avx, . - enable_avx

.data
fcw_init: 
    .word 0x037F