1 /* $OpenBSD: strncmp.S,v 1.3 2005/08/07 11:30:38 espie Exp $ */ 2 /* 3 * Written by J.T. Conklin <jtc (at) netbsd.org>. 4 * Public domain. 5 */ 6 7 #include <private/bionic_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 114 END(strncmp) 115
