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MAEC TOOL NEWS:
MAECT-M3T-NC30WA-021216D
A Note on C Compiler
M3T-NC30WA
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Please take note of the following problem in using C compiler (with an assembler and integrated development environment) M3T-NC30WA for the M16C/60, M16C/30, M16C/20, and M16C/10 series MCUs:
- On calling assembler macro functions
- Versions Concerned
M3T-NC30WA V.5.00 Release 1 and Release 2
- Description
An rts or exitd instruction may not be generated at the final line of the function calling an assembler macro.
- Conditions
- This problem occurs if the following four conditions are satisfied:
- (1) A function calls an assembler macro at its final line.
- (2) The function calling an assembler macro is described such a way that no stack frame is constructed.
- (3) The optimizing option -OR or -OS is selected.
- (4) The -genter option is not selected.
- Example
---------------------------------------------
static void b(int);
#pragma __ASMMACRO b(R0)
#pragma ASM
_b .macro
mov.w R0,R1
.endm
#pragma ENDASM
void a(void) /* an rts instruction not created
at the last of the function a */
{
b(2);
}
---------------------------------------------
- Workaround
- This problem can be circumvented in either of the following ways:
- (1) Select the -genter option.
- (2) Place a dummy asm function immediately after the line calling an assembler macro.
[Example]
---------------------------------------------
static void b(int);
#pragma __ASMMACRO b(R0);
#pragma ASM
_b .macro
mov.w R0,R1
.endm
#pragma ENDASM
void a(void)
{
b(2);
asm(); /* Place a dummy asm function */
}
---------------------------------------------
- Schedule of Fixing the Problem
We plan to fix this problem in our next release of the product.
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