📄 lib_str.lst
字号:
\ 00000020 7047 BX LR ;; return
295 }
296
297
298 /*$PAGE*/
299 /*
300 *********************************************************************************************************
301 * Str_Copy()
302 *
303 * Description : Copy source string to destination string buffer.
304 *
305 * Argument(s) : pstr_dest Pointer to destination string buffer to receive source string copy (see Note #1a).
306 *
307 * pstr_src Pointer to source string to copy into destination string buffer (see Note #1b).
308 *
309 * Return(s) : Pointer to destination string, if NO error(s) [see Note #2b1].
310 *
311 * Pointer to NULL, otherwise (see Note #2b2A).
312 *
313 * Caller(s) : Application.
314 *
315 * Note(s) : (1) (a) Destination buffer size NOT validated; buffer overruns MUST be prevented by caller.
316 *
317 * (1) Destination buffer size MUST be large enough to accommodate the entire source
318 * string size including the terminating NULL character.
319 *
320 * (b) Source buffer NOT modified.
321 *
322 * (2) (a) IEEE Std 1003.1, 2004 Edition, Section 'strcpy() : DESCRIPTION' states that :
323 *
324 * (1) "The strcpy() function shall copy the string pointed to by 's2' ('pstr_src')
325 * ... into the array pointed to by 's1' ('pstr_dest')" ...
326 * (2) "(including the terminating null byte)."
327 *
328 * (b) IEEE Std 1003.1, 2004 Edition, Section 'strcpy() : RETURN VALUE' states that :
329 *
330 * (1) "The strcpy() function shall return 's1' ('pstr_dest');" ...
331 * (2) "no return value is reserved to indicate an error."
332 * (A) #### This requirement is intentionally NOT implemented in order to return
333 * NULL for any error(s).
334 *
335 * (c) IEEE Std 1003.1, 2004 Edition, Section 'strcpy() : DESCRIPTION' states that "if
336 * copying takes place between objects that overlap, the behavior is undefined".
337 *
338 * (3) String copy terminates when :
339 *
340 * (a) Destination/Source string pointer(s) are passed NULL pointers.
341 * (1) No string copy performed; NULL pointer returned.
342 *
343 * (b) Destination/Source string pointer(s) point to NULL.
344 * (1) String buffer(s) overlap with NULL address; NULL pointer returned.
345 *
346 * (c) Source string's terminating NULL character found.
347 * (1) Entire source string copied into destination string buffer (see Note #2a).
348 *********************************************************************************************************
349 */
350
\ In section .text, align 2, keep-with-next
351 CPU_CHAR *Str_Copy ( CPU_CHAR *pstr_dest,
352 const CPU_CHAR *pstr_src)
353 {
\ Str_Copy:
\ 00000000 70B5 PUSH {R4-R6,LR}
\ 00000002 0400 MOVS R4,R0
\ 00000004 0D00 MOVS R5,R1
354 CPU_CHAR *pstr_rtn;
355
356
357 pstr_rtn = Str_Copy_N(pstr_dest,
358 pstr_src,
359 DEF_INT_CPU_U_MAX_VAL);
\ 00000006 5FF0FF32 MOVS R2,#-1
\ 0000000A 2900 MOVS R1,R5
\ 0000000C 2000 MOVS R0,R4
\ 0000000E ........ BL Str_Copy_N
\ 00000012 0600 MOVS R6,R0
360
361 return (pstr_rtn);
\ 00000014 3000 MOVS R0,R6
\ 00000016 70BD POP {R4-R6,PC} ;; return
362 }
363
364
365 /*$PAGE*/
366 /*
367 *********************************************************************************************************
368 * Str_Copy_N()
369 *
370 * Description : Copy source string to destination string buffer, up to a maximum number of characters.
371 *
372 * Argument(s) : pstr_dest Pointer to destination string buffer to receive source string copy (see Note #1a).
373 *
374 * pstr_src Pointer to source string to copy into destination string buffer (see Note #1b).
375 *
376 * len_max Maximum number of characters to copy (see Notes #2a2 & #3d).
377 *
378 * Return(s) : Pointer to destination string, if NO error(s) [see Note #2b1].
379 *
380 * Pointer to NULL, otherwise (see Note #2b2A).
381 *
382 * Caller(s) : Application.
383 *
384 * Note(s) : (1) (a) Destination buffer size NOT validated; buffer overruns MUST be prevented by caller.
385 *
386 * (1) Destination buffer size MUST be large enough to accommodate the entire source
387 * string size including the terminating NULL character.
388 *
389 * (b) Source string buffer NOT modified.
390 *
391 * (2) (a) (1) IEEE Std 1003.1, 2004 Edition, Section 'strncpy() : DESCRIPTION' states that :
392 *
393 * (A) "The strncpy() function shall copy ... the array pointed to by 's2'
394 * ('pstr_src') to the array pointed to by 's1' ('pstr_dest')"; ...
395 * (B) but "not more than 'n' ('len_max') bytes" ...
396 * (C) & "(bytes that follow a null byte are not copied)".
397 *
398 * (2) (A) IEEE Std 1003.1, 2004 Edition, Section 'strncpy() : DESCRIPTION' adds that
399 * "if the array pointed to by 's2' ('pstr_src') is a string that is shorter
400 * than 'n' ('len_max') bytes, null bytes shall be appended to the copy in
401 * the array pointed to by 's1' ('pstr_dest'), until 'n' ('len_max') bytes
402 * in all are written."
403 *
404 * (1) #### Since Str_Copy() limits the maximum number of characters to copy
405 * via Str_Copy_N() by the CPU's maximum number of addressable characters,
406 * this requirement is intentionally NOT implemented to avoid appending
407 * a potentially large number of unnecessary terminating NULL characters.
408 *
409 * (B) IEEE Std 1003.1, 2004 Edition, Section 'strncpy() : APPLICATION USAGE' also
410 * states that "if there is no null byte in the first 'n' ('len_max') bytes of
411 * the array pointed to by 's2' ('pstr_src'), the result is not null-terminated".
412 *
413 * (b) IEEE Std 1003.1, 2004 Edition, Section 'strncpy() : RETURN VALUE' states that :
414 *
415 * (1) "The strncpy() function shall return 's1' ('pstr_dest');" ...
416 * (2) "no return value is reserved to indicate an error."
417 * (A) #### This requirement is intentionally ignored in order to return NULL
418 * for any error(s).
419 *
420 * (c) IEEE Std 1003.1, 2004 Edition, Section 'strncpy() : DESCRIPTION' states that "if
421 * copying takes place between objects that overlap, the behavior is undefined".
422 *
423 * (3) String copy terminates when :
424 *
425 * (a) Destination/Source string pointer(s) are passed NULL pointers.
426 * (1) No string copy performed; NULL pointer returned.
427 *
428 * (b) Destination/Source string pointer(s) point to NULL.
429 * (1) String buffer(s) overlap with NULL address; NULL pointer returned.
430 *
431 * (c) Source string's terminating NULL character found.
432 * (1) Entire source string copied into destination string buffer (see Note #2a1A).
433 *
434 * (d) 'len_max' number of characters copied.
435 * (1) 'len_max' number of characters MAY include the terminating NULL character
436 * (see Note #2a1C).
437 * (2) Null copies allowed (i.e. zero-length copies).
438 * (A) No string copy performed; destination string returned (see Note #2b1).
439 *********************************************************************************************************
440 */
441 /*$PAGE*/
\ In section .text, align 2, keep-with-next
442 CPU_CHAR *Str_Copy_N ( CPU_CHAR *pstr_dest,
443 const CPU_CHAR *pstr_src,
444 CPU_SIZE_T len_max)
445 {
\ Str_Copy_N:
\ 00000000 70B4 PUSH {R4-R6}
\ 00000002 0300 MOVS R3,R0
446 CPU_CHAR *pstr_copy_dest;
447 const CPU_CHAR *pstr_copy_src;
448 CPU_SIZE_T len_copy;
449
450 /* Rtn NULL if str ptr(s) NULL (see Note #3a1). */
451 if (pstr_dest == (CPU_CHAR *)0) {
\ 00000004 002B CMP R3,#+0
\ 00000006 01D1 BNE.N ??Str_Copy_N_0
452 return ((CPU_CHAR *)0);
\ 00000008 0020 MOVS R0,#+0
\ 0000000A 21E0 B.N ??Str_Copy_N_1
453 }
454 if (pstr_src == (const CPU_CHAR *)0) {
\ ??Str_Copy_N_0:
\ 0000000C 0029 CMP R1,#+0
\ 0000000E 01D1 BNE.N ??Str_Copy_N_2
455 return ((CPU_CHAR *)0);
\ 00000010 0020 MOVS R0,#+0
\ 00000012 1DE0 B.N ??Str_Copy_N_1
456 }
457
458
459 pstr_copy_dest = pstr_dest;
\ ??Str_Copy_N_2:
\ 00000014 1C00 MOVS R4,R3
460 pstr_copy_src = pstr_src;
\ 00000016 0D00 MOVS R5,R1
461 len_copy = 0u;
\ 00000018 0020 MOVS R0,#+0
\ 0000001A 0600 MOVS R6,R0
⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -