| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/arch/m32r/strlen.S -- strlen code. |
| 3 | * |
| 4 | * Copyright (C) 2001 Hirokazu Takata |
| 5 | * |
| 6 | * size_t strlen(const char *s); |
| 7 | * |
| 8 | */ |
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 9 | |
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 10 | #include <linux/linkage.h> |
| 11 | #include <asm/assembler.h> |
| 12 | |
| 13 | #ifdef CONFIG_ISA_DUAL_ISSUE |
| 14 | |
| 15 | .text |
| 16 | ENTRY(strlen) |
| 17 | mv r6, r0 || ldi r2, #0 |
| 18 | and3 r0, r0, #3 |
| 19 | bnez r0, strlen_byte |
| 20 | ; |
| 21 | strlen_word: |
| 22 | ld r0, @r6+ |
| 23 | ; |
| 24 | seth r5, #high(0x01010101) |
| 25 | or3 r5, r5, #low(0x01010101) |
| 26 | sll3 r7, r5, #7 |
| 27 | strlen_word_loop: |
| 28 | ld r1, @r6+ || not r4, r0 |
| 29 | sub r0, r5 || and r4, r7 |
| 30 | and r4, r0 |
| 31 | bnez r4, strlen_last_bytes |
| 32 | ld r0, @r6+ || not r4, r1 |
| 33 | sub r1, r5 || and r4, r7 |
| 34 | and r4, r1 || addi r2, #4 |
| 35 | bnez r4, strlen_last_bytes |
| 36 | addi r2, #4 || bra.s strlen_word_loop |
| 37 | |
| 38 | ; NOTE: If a null char. exists, return 0. |
| 39 | ; if ((x - 0x01010101) & ~x & 0x80808080) |
| 40 | ; return 0; |
| 41 | ; |
| 42 | strlen_byte: |
| 43 | ldb r1, @r6 || addi r6, #1 |
| 44 | beqz r1, strlen_exit |
| 45 | addi r2, #1 || bra.s strlen_byte |
| 46 | ; |
| 47 | strlen_last_bytes: |
| 48 | ldi r0, #4 || addi r6, #-8 |
| 49 | ; |
| 50 | strlen_byte_loop: |
| 51 | ldb r1, @r6 || addi r6, #1 |
| 52 | addi r0, #-1 || cmpz r1 |
| 53 | bc.s strlen_exit || cmpz r0 |
| 54 | addi r2, #1 || bnc.s strlen_byte_loop |
| 55 | ; |
| 56 | strlen_exit: |
| 57 | mv r0, r2 || jmp r14 |
| 58 | |
| 59 | #else /* not CONFIG_ISA_DUAL_ISSUE */ |
| 60 | |
| 61 | .text |
| 62 | ENTRY(strlen) |
| 63 | mv r6, r0 |
| 64 | ldi r2, #0 |
| 65 | and3 r0, r0, #3 |
| 66 | bnez r0, strlen_byte |
| 67 | ; |
| 68 | strlen_word: |
| 69 | ld r0, @r6+ |
| 70 | ; |
| 71 | seth r5, #high(0x01010101) |
| 72 | or3 r5, r5, #low(0x01010101) |
| 73 | sll3 r7, r5, #7 |
| 74 | strlen_word_loop: |
| 75 | ld r1, @r6+ |
| 76 | not r4, r0 ; NOTE: If a null char. exists, return 0. |
| 77 | sub r0, r5 ; if ((x - 0x01010101) & ~x & 0x80808080) |
| 78 | and r4, r7 ; return 0; |
| 79 | and r4, r0 |
| 80 | bnez r4, strlen_last_bytes |
| 81 | addi r2, #4 |
| 82 | ; |
| 83 | ld r0, @r6+ |
| 84 | not r4, r1 ; NOTE: If a null char. exists, return 0. |
| 85 | sub r1, r5 ; if ((x - 0x01010101) & ~x & 0x80808080) |
| 86 | and r4, r7 ; return 0; |
| 87 | and r4, r1 |
| 88 | bnez r4, strlen_last_bytes |
| 89 | addi r2, #4 |
| 90 | bra strlen_word_loop |
| 91 | ; |
| 92 | strlen_byte: |
| 93 | ldb r1, @r6 |
| 94 | addi r6, #1 |
| 95 | beqz r1, strlen_exit |
| 96 | addi r2, #1 |
| 97 | bra strlen_byte |
| 98 | ; |
| 99 | strlen_last_bytes: |
| 100 | ldi r0, #4 |
| 101 | addi r6, #-8 |
| 102 | ; |
| 103 | strlen_byte_loop: |
| 104 | ldb r1, @r6 |
| 105 | addi r6, #1 |
| 106 | addi r0, #-1 |
| 107 | beqz r1, strlen_exit |
| 108 | addi r2, #1 |
| 109 | bnez r0, strlen_byte_loop |
| 110 | ; |
| 111 | strlen_exit: |
| 112 | mv r0, r2 |
| 113 | jmp r14 |
| 114 | |
| 115 | #endif /* not CONFIG_ISA_DUAL_ISSUE */ |
| 116 | |
| 117 | .end |