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.text
/*
* fillMemory.
*
* rdi - length.
* rsi - pointer.
* rdx - value filled with a byte.
*/
.globl _D5tanya6memory2op10fillMemoryFNaNbNiAvmZv
.type _D5tanya6memory2op10fillMemoryFNaNbNiAvmZv, @function
_D5tanya6memory2op10fillMemoryFNaNbNiAvmZv:
// Check for zero length
test %rdi, %rdi
jz end
mov %rdi, %rax
mov %rsi, %r8
movq %rdx, %xmm0
movlhps %xmm0, %xmm0
// Check if the pointer is aligned to a 16-byte boundary
and $-0x10, %r8
// Compute the number of misaligned bytes
mov %rsi, %r9
sub %r8, %r9
test %r9, %r9
jz aligned
// Get the number of bytes to be written until we are aligned
mov $0x10, %rcx
sub %r9, %rcx
mov %rsi, %r8
// If the length is less than the number of misaligned bytes,
// write one byte at a time and exit
cmp %rax, %rcx
jg aligned_1
naligned:
mov %dl, (%r8) // Write a byte
// Advance the pointer. Decrease the total number of bytes
// and the misaligned ones
inc %r8
dec %rcx
dec %rax
// Checks if we are aligned
test %rcx, %rcx
jnz naligned
aligned:
// Checks if we're done writing bytes
test %rax, %rax
jz end
// Write 1 byte at a time
cmp $8, %rax
jl aligned_1
// Write 8 bytes at a time
cmp $16, %rax
jl aligned_8
// Write 16 bytes at a time
cmp $32, %rax
jl aligned_16
// Write 32 bytes at a time
cmp $64, %rax
jl aligned_32
aligned_64:
movdqa %xmm0, (%r8)
movdqa %xmm0, 16(%r8)
movdqa %xmm0, 32(%r8)
movdqa %xmm0, 48(%r8)
add $64, %r8
sub $64, %rax
cmp $64, %rax
jge aligned_64
// Checks if we're done writing bytes
test %rax, %rax
jz end
// Write 1 byte at a time
cmp $8, %rax
jl aligned_1
// Write 8 bytes at a time
cmp $16, %rax
jl aligned_8
// Write 16 bytes at a time
cmp $32, %rax
jl aligned_16
aligned_32:
movdqa %xmm0, (%r8)
movdqa %xmm0, 16(%r8)
add $32, %r8
sub $32, %rax
// Checks if we're done writing bytes
test %rax, %rax
jz end
// Write 1 byte at a time
cmp $8, %rax
jl aligned_1
// Write 8 bytes at a time
cmp $16, %rax
jl aligned_8
aligned_16:
movdqa %xmm0, (%r8)
add $16, %r8
sub $16, %rax
// Checks if we're done writing bytes
test %rax, %rax
jz end
// Write 1 byte at a time
cmp $8, %rax
jl aligned_1
aligned_8:
mov %rdx, (%r8)
add $8, %r8
sub $8, %rax
// Checks if we're done writing bytes
test %rax, %rax
jz end
aligned_1:
mov %dl, (%r8)
inc %r8
dec %rax
test %rax, %rax
jnz aligned_1
end:
ret
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