| Greg Hartman | 76d05dc | 2016-11-23 15:51:27 -0800 | [diff] [blame] | 1 | /* ----------------------------------------------------------------------- * |
| 2 | * |
| 3 | * Copyright 2008 H. Peter Anvin - All Rights Reserved |
| 4 | * |
| 5 | * Permission is hereby granted, free of charge, to any person |
| 6 | * obtaining a copy of this software and associated documentation |
| 7 | * files (the "Software"), to deal in the Software without |
| 8 | * restriction, including without limitation the rights to use, |
| 9 | * copy, modify, merge, publish, distribute, sublicense, and/or |
| 10 | * sell copies of the Software, and to permit persons to whom |
| 11 | * the Software is furnished to do so, subject to the following |
| 12 | * conditions: |
| 13 | * |
| 14 | * The above copyright notice and this permission notice shall |
| 15 | * be included in all copies or substantial portions of the Software. |
| 16 | * |
| 17 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
| 18 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES |
| 19 | * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
| 20 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT |
| 21 | * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, |
| 22 | * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
| 23 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR |
| 24 | * OTHER DEALINGS IN THE SOFTWARE. |
| 25 | * |
| 26 | * ----------------------------------------------------------------------- */ |
| 27 | |
| 28 | /* |
| 29 | * memcpy.S |
| 30 | * |
| 31 | * Reasonably efficient memcpy, using aligned transfers at least |
| 32 | * for the destination operand. |
| 33 | */ |
| 34 | |
| 35 | .text |
| 36 | .globl memcpy |
| 37 | .type memcpy, @function |
| 38 | memcpy: |
| 39 | movl 0xc(%esp),%ecx |
| 40 | movl 0x8(%esp),%edx |
| 41 | movl 0x4(%esp),%eax |
| 42 | |
| 43 | jecxz 1f |
| 44 | |
| 45 | pushl %esi |
| 46 | pushl %edi |
| 47 | pushl %eax /* Return value */ |
| 48 | |
| 49 | movl %eax,%edi |
| 50 | movl %edx,%esi |
| 51 | |
| 52 | /* Initial alignment */ |
| 53 | movl %edi,%edx |
| 54 | shrl $1,%edx |
| 55 | jnc 11f |
| 56 | movsb |
| 57 | decl %ecx |
| 58 | 11: |
| 59 | movb %cl,%al |
| 60 | cmpl $2,%ecx |
| 61 | jb 13f |
| 62 | |
| 63 | shrl $1,%edx |
| 64 | jnc 12f |
| 65 | movsw |
| 66 | subl $2,%ecx |
| 67 | 12: |
| 68 | /* Bulk transfer */ |
| 69 | movb %cl,%al |
| 70 | shrl $2,%ecx |
| 71 | rep; movsl |
| 72 | |
| 73 | /* Final alignment */ |
| 74 | testb $2,%al |
| 75 | jz 14f |
| 76 | movsw |
| 77 | 13: |
| 78 | 14: |
| 79 | testb $1,%al |
| 80 | jz 15f |
| 81 | movsb |
| 82 | 15: |
| 83 | |
| 84 | popl %eax /* Return value */ |
| 85 | popl %edi |
| 86 | popl %esi |
| 87 | 1: |
| 88 | ret |
| 89 | |
| 90 | .size memcpy, .-memcpy |