| // Copyright 2021 The Fuchsia Authors |
| // |
| // Use of this source code is governed by a MIT-style |
| // license that can be found in the LICENSE file or at |
| // https://opensource.org/licenses/MIT |
| |
| #include <lib/arch/asm.h> |
| |
| .text |
| |
| // memcpy implementation that copies 8 bytes at a time when possible |
| // %rax = memcpy_movsq(%rdi, %rsi, %rdx) |
| .function memcpy_movsq, global |
| // Save return value. |
| mov %rdi, %rax |
| |
| // Copy all of the 8 byte chunks we can |
| mov %rdx, %rcx |
| shr $3, %rcx |
| rep movsq // while (rcx-- > 0) { *rdi++ = *rsi++; /* rdi, rsi are uint64_t* */ } |
| |
| // Copy the rest |
| mov %rdx, %rcx |
| and $0x7, %rcx |
| rep movsb |
| ret |
| .end_function |
