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RENESAS TOOL NEWS on March 1, 2005: RSO-M3T-NC30WA_4-050301D
A Note on Using
C-Compiler Package M3T-NC30WA
--On Calling String Handling Functions in the Standard Library--
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Please take note of the following problem in using the M3T-NC30WA
C-compiler package, which is used for the M16C/60, M16C/30, M16C/Tiny,
M16C/20, M16C/10, and R8C/Tiny series of MCUs:
- On calling string handling functions in the standard library
- Versions Concerned
M3T-NC30WA V.5.00 Release 1 through V.5.30 Release 02
- Description
If a source program that calls a library function declared in the
standard header file <string.h> is compiled, an application error may
arise, resulting in compilation being unsuccessfully terminated.
- 2.1 Conditions
- This problem may occur if the following conditions are all satisfied.
If no application error arises, however, code is properly generated:
| (1) | Compile option -OR is selected. |
| (2) | Compile option -Ono_stdlib(-ONS) is not selected. |
| (3) | A function makes calls to a library function twice or more. |
| (4) | The library function called twice or more in (3) is any of the following:
memcmp, memcpy, memicmp, memmove, strcat, strcmp, strcoll, strcpy, strcspn, stricmp, strncat, strncmp, strncpy, strnicmp, strpbrk, strspn, strstr, and strxfrm
(All the above functions take two parameters of type pointer.) |
| (5) | At any of the calls to the library function in (3), far pointers
(including address constants) are passed to both of the parameters. |
| (6) | The same function to which far pointers were passed in (5) is
again called later, and a far pointer (including an address
constant) is passed to either of the parameters, and a near pointer
to the other. |
| (7) | At both calls in (5) and (6), the return value of the function in (3) is not referenced. |
| (8) | After both calls in (5) and (6), both the flows of processing
merge. (If not so explicitly in the source program, optimization may bring such a result.) |
- 2.2 Example
-----------------------------------------------------------------------
#include <string.h>
char near nearstr[10];
char far far1str[10], far2str[10];
int cond;
void func(void)
{
if (cond == 0x0001) {
strcpy(nearstr, far2str); /* Conditions (3), (4), (6), and (7) */
} else {
strcpy(far1str, far2str); /* Conditions (3), (4), (5), and (7) */
}
cond = 0; /* Condition (8) */
}
-----------------------------------------------------------------------
- Workaround
Select compile option -Ono_stdlib(-ONS) in addition to -OR.
- Schedule of Fixing the Problem
We plan to fix this problem in the next release of the product.
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