github.com/afumu/libc@v0.0.6/musl/src/math/x86_64/floorl.s (about)

     1  .global floorl
     2  .type floorl,@function
     3  floorl:
     4  	fldt 8(%rsp)
     5  1:	mov $0x7,%al
     6  1:	fstcw 8(%rsp)
     7  	mov 9(%rsp),%ah
     8  	mov %al,9(%rsp)
     9  	fldcw 8(%rsp)
    10  	frndint
    11  	mov %ah,9(%rsp)
    12  	fldcw 8(%rsp)
    13  	ret
    14  
    15  .global ceill
    16  .type ceill,@function
    17  ceill:
    18  	fldt 8(%rsp)
    19  	mov $0xb,%al
    20  	jmp 1b
    21  
    22  .global truncl
    23  .type truncl,@function
    24  truncl:
    25  	fldt 8(%rsp)
    26  	mov $0xf,%al
    27  	jmp 1b