projects / unix-history / blame
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1 | /* |
| 2 | * Copyright (c) 1985 Regents of the University of California. | |
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3 | * All rights reserved. |
| 4 | * | |
| 5 | * Redistribution and use in source and binary forms are permitted | |
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6 | * provided that the above copyright notice and this paragraph are |
| 7 | * duplicated in all such forms and that any documentation, | |
| 8 | * advertising materials, and other materials related to such | |
| 9 | * distribution and use acknowledge that the software was developed | |
| 10 | * by the University of California, Berkeley. The name of the | |
| 11 | * University may not be used to endorse or promote products derived | |
| 12 | * from this software without specific prior written permission. | |
| 13 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR | |
| 14 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED | |
| 15 | * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. | |
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16 | */ |
| 17 | ||
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18 | #if defined(LIBC_SCCS) && !defined(lint) |
| 19 | .asciz "@(#)gets.s 5.4 (Berkeley) %G%" | |
| 20 | #endif /* LIBC_SCCS and not lint */ | |
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21 | |
| 22 | /* | |
| 23 | * char *gets(s); | |
| 24 | * char *s; | |
| 25 | * | |
| 26 | * argument: a target string | |
| 27 | * side effects: reads bytes up to and including a newline from the | |
| 28 | * standard input into the target string and replaces the newline | |
| 29 | * with a null to null-terminate the string. | |
| 30 | * result: the target string if successful, 0 otherwise. | |
| 31 | */ | |
| 32 | ||
| 33 | #include "DEFS.h" | |
| 34 | ||
| 35 | #define NL 0xa | |
| 36 | ||
| 37 | ENTRY(gets, R11|R10) | |
| 38 | ||
| 39 | #define S r11 | |
| 40 | movl 4(ap),S | |
| 41 | #define IPTR r10 | |
| 42 | #define _CNT | |
| 43 | #define _PTR 4 | |
| 44 | #define _BASE 8 | |
| 45 | #define _BUFSIZ 12 | |
| 46 | #define _FLAG 16 | |
| 47 | movab __iob,IPTR | |
| 48 | ||
| 49 | #define OLD_S 4(ap) | |
| 50 | ||
| 51 | /* | |
| 52 | * If no characters, call _filbuf() to get some. | |
| 53 | */ | |
| 54 | tstl _CNT(IPTR) | |
| 55 | jgtr Lscan | |
| 56 | ||
| 57 | Lloop: | |
| 58 | pushl IPTR | |
| 59 | calls $1,__filbuf | |
| 60 | tstl r0 /* What did _filbuf() return? */ | |
| 61 | jlss Leof | |
| 62 | cmpb r0,$NL | |
| 63 | jneq 1f | |
| 64 | clrb (S) | |
| 65 | jbr Lret | |
| 66 | 1: | |
| 67 | movb r0,(S)+ /* Save the returned character */ | |
| 68 | tstl _BASE(IPTR) /* Is input buffered? */ | |
| 69 | jeql Lloop | |
| 70 | ||
| 71 | /* | |
| 72 | * Look for a newline in the buffer. | |
| 73 | */ | |
| 74 | Lscan: | |
| 75 | locc $NL,_CNT(IPTR),*_PTR(IPTR) | |
| 76 | jeql Lagain | |
| 77 | ||
| 78 | /* | |
| 79 | * Success -- copy the data and return. | |
| 80 | */ | |
| 81 | subl3 r0,_CNT(IPTR),r2 | |
| 82 | subl2 r2,_CNT(IPTR) | |
| 83 | movc3 r2,*_PTR(IPTR),(S) /* Copy the data */ | |
| 84 | clrb (r3) | |
| 85 | movl r1,_PTR(IPTR) | |
| 86 | decl _CNT(IPTR) /* Skip the newline */ | |
| 87 | incl _PTR(IPTR) | |
| 88 | ||
| 89 | /* | |
| 90 | * Normal return. | |
| 91 | */ | |
| 92 | Lret: | |
| 93 | movl OLD_S,r0 | |
| 94 | ret | |
| 95 | ||
| 96 | /* | |
| 97 | * If we run out of characters, copy the buffer and loop. | |
| 98 | */ | |
| 99 | Lagain: | |
| 100 | movc3 _CNT(IPTR),*_PTR(IPTR),(S) /* Copy the data */ | |
| 101 | movl r3,S | |
| 102 | movl _BASE(IPTR),_PTR(IPTR) /* Reset stdio */ | |
| 103 | clrl _CNT(IPTR) | |
| 104 | jbr Lloop | |
| 105 | ||
| 106 | /* | |
| 107 | * End of file? Check to see if we copied any data. | |
| 108 | */ | |
| 109 | Leof: | |
| 110 | cmpl S,OLD_S | |
| 111 | jeql Lerror | |
| 112 | clrb (S) | |
| 113 | jbr Lret | |
| 114 | ||
| 115 | /* | |
| 116 | * Error/eof return -- null pointer. | |
| 117 | */ | |
| 118 | Lerror: | |
| 119 | clrl r0 | |
| 120 | ret |