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MESC TOOL NEWS:
MESCT-NC308WA-000116D
NC308WA, NC30WA, NC79WA, and NC77WA
Precautions
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Please take note of the following problem in using C compilers (with assembler and integrated development environment) NC308WA, NC30WA, NC79WA, and NC77WA:
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Products Concerned
| NC308WA V.2.00 Release 1 | C compiler for the M16C/80 series MCUs |
| NC30WA V.3.20 Release 1 | C compiler for the M16C/60 and M16C/20 series MCUs |
| NC79WA V.3.20 Release 1 | C compiler for the 7900 series MCUs |
| NC77WA V.5.20 Release 1 | C compiler for the 77xx series MCUs |
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Problem
Initialization of external variables of type float or double may result in incorrect values being assigned.
- 2.1 Conditions
- This problem occurs if the following four conditions are satisfied:
- (1)External variables are initialized.
- (2)The external variables are of type float or double.
- (3)The external variables are types of aggregate (struct, union, or array).
- (4)Variables of type float or double are continuously described in an aggregate.
- 2.2 Examples
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Structure
struct S {
double d;
float f;
long l;
} s = {0.5, 0.6, 0};
Array
double d[5] = {0.5, 0.6, 0.7, 0.8, 0.9};
union {
float f;
long l;
} u[5] = {0.5, 0.6, 0.7, 0.8, 0.9};
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Workaround
- 3.1 Structure
- Describe variables of type float or double discontinuously. If they will be continuously placed, see Section 3.2.
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[Example of Description]
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struct S {
double d;
long l; /* Place a member of type other than float or double */
float f;
} s = {0.5, 0, 0.6};
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- 3.2 Array
- Assign an initial value within each function.
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[Example of Description]
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double d[5];
void init(void)
{
d[0] = 0.5;
d[1] = 0.6;
d[2] = 0.7;
d[3] = 0.8;
d[4] = 0.9;
}
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Schedule of Fixing Problem
We plan to fix this problem in our next release.
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