| The Android Open Source Project | 1dc9e47 | 2009-03-03 19:28:35 -0800 | [diff] [blame] | 1 | /* $OpenBSD: strncmp.S,v 1.3 2005/08/07 11:30:38 espie Exp $ */ |
| 2 | /* |
| 3 | * Written by J.T. Conklin <jtc@netbsd.org>. |
| 4 | * Public domain. |
| 5 | */ |
| 6 | |
| 7 | #include <machine/asm.h> |
| 8 | |
| 9 | /* |
| 10 | * NOTE: I've unrolled the loop eight times: large enough to make a |
| 11 | * significant difference, and small enough not to totally trash the |
| 12 | * cache. |
| 13 | */ |
| 14 | |
| 15 | ENTRY(strncmp) |
| 16 | pushl %ebx |
| 17 | movl 8(%esp),%eax |
| 18 | movl 12(%esp),%ecx |
| 19 | movl 16(%esp),%edx |
| 20 | testl %edx,%edx |
| 21 | jmp L2 /* Jump into the loop! */ |
| 22 | |
| 23 | .align 2,0x90 |
| 24 | L1: incl %eax |
| 25 | incl %ecx |
| 26 | decl %edx |
| 27 | L2: jz L4 /* strings are equal */ |
| 28 | movb (%eax),%bl |
| 29 | testb %bl,%bl |
| 30 | jz L3 |
| 31 | cmpb %bl,(%ecx) |
| 32 | jne L3 |
| 33 | |
| 34 | incl %eax |
| 35 | incl %ecx |
| 36 | decl %edx |
| 37 | jz L4 |
| 38 | movb (%eax),%bl |
| 39 | testb %bl,%bl |
| 40 | jz L3 |
| 41 | cmpb %bl,(%ecx) |
| 42 | jne L3 |
| 43 | |
| 44 | incl %eax |
| 45 | incl %ecx |
| 46 | decl %edx |
| 47 | jz L4 |
| 48 | movb (%eax),%bl |
| 49 | testb %bl,%bl |
| 50 | jz L3 |
| 51 | cmpb %bl,(%ecx) |
| 52 | jne L3 |
| 53 | |
| 54 | incl %eax |
| 55 | incl %ecx |
| 56 | decl %edx |
| 57 | jz L4 |
| 58 | movb (%eax),%bl |
| 59 | testb %bl,%bl |
| 60 | jz L3 |
| 61 | cmpb %bl,(%ecx) |
| 62 | jne L3 |
| 63 | |
| 64 | incl %eax |
| 65 | incl %ecx |
| 66 | decl %edx |
| 67 | jz L4 |
| 68 | movb (%eax),%bl |
| 69 | testb %bl,%bl |
| 70 | jz L3 |
| 71 | cmpb %bl,(%ecx) |
| 72 | jne L3 |
| 73 | |
| 74 | incl %eax |
| 75 | incl %ecx |
| 76 | decl %edx |
| 77 | jz L4 |
| 78 | movb (%eax),%bl |
| 79 | testb %bl,%bl |
| 80 | jz L3 |
| 81 | cmpb %bl,(%ecx) |
| 82 | jne L3 |
| 83 | |
| 84 | incl %eax |
| 85 | incl %ecx |
| 86 | decl %edx |
| 87 | jz L4 |
| 88 | movb (%eax),%bl |
| 89 | testb %bl,%bl |
| 90 | jz L3 |
| 91 | cmpb %bl,(%ecx) |
| 92 | jne L3 |
| 93 | |
| 94 | incl %eax |
| 95 | incl %ecx |
| 96 | decl %edx |
| 97 | jz L4 |
| 98 | movb (%eax),%bl |
| 99 | testb %bl,%bl |
| 100 | jz L3 |
| 101 | cmpb %bl,(%ecx) |
| 102 | je L1 |
| 103 | |
| 104 | .align 2,0x90 |
| 105 | L3: movzbl (%eax),%eax /* unsigned comparision */ |
| 106 | movzbl (%ecx),%ecx |
| 107 | subl %ecx,%eax |
| 108 | popl %ebx |
| 109 | ret |
| 110 | .align 2,0x90 |
| 111 | L4: xorl %eax,%eax |
| 112 | popl %ebx |
| 113 | ret |
| Elliott Hughes | 6719500 | 2013-02-13 15:12:32 -0800 | [diff] [blame] | 114 | END(strncmp) |