Difference between revisions of "Literal expression"
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{{MSXGL}} is using sdcc11 option for compile C code that is described as « ''Generally follow the [https://en.wikipedia.org/wiki/C11_(C_standard_revision) ISO C11 standard], but allow some SDCC behaviour that conflicts with the standard'' ». | {{MSXGL}} is using sdcc11 option for compile C code that is described as « ''Generally follow the [https://en.wikipedia.org/wiki/C11_(C_standard_revision) ISO C11 standard], but allow some SDCC behaviour that conflicts with the standard'' ». | ||
| + | |||
| + | For literal expressions, the C11 standard applies. | ||
| + | These expressions are interpreted during the preprocessing phase and are replaced by their final value for compilation. | ||
| + | |||
| + | For example: | ||
| + | <syntaxhighlight lang="c"> | ||
| + | u8 a = (10 * 5) - 12; // 38 | ||
| + | i16 b = 8 * 1024 / 3; // 2730 | ||
| + | i8 c = 3.141593 * -10; // -31 (generate warning) | ||
| + | </syntaxhighlight> | ||
| + | |||
| + | To help the preprocessor to determine the type of numbers you can either: | ||
| + | * Cast the number or/and the result to the type of your choice, | ||
| + | <syntaxhighlight lang="c"> | ||
| + | u8 d = (u8)(255-1); | ||
| + | i16 e = (i16)(66000/3); | ||
| + | </syntaxhighlight> | ||
| + | * Use C11 postfix U, L or LL. | ||
| + | <syntaxhighlight lang="txt"> | ||
| + | U: Unsigned integer | ||
| + | L: 32-bits integer | ||
| + | LL: 64-bits integer | ||
| + | </syntaxhighlight> | ||
Latest revision as of 21:25, 13 January 2024
MSXGL is using sdcc11 option for compile C code that is described as « Generally follow the ISO C11 standard, but allow some SDCC behaviour that conflicts with the standard ».
For literal expressions, the C11 standard applies. These expressions are interpreted during the preprocessing phase and are replaced by their final value for compilation.
For example:
u8 a = (10 * 5) - 12; // 38 i16 b = 8 * 1024 / 3; // 2730 i8 c = 3.141593 * -10; // -31 (generate warning)
To help the preprocessor to determine the type of numbers you can either:
- Cast the number or/and the result to the type of your choice,
u8 d = (u8)(255-1); i16 e = (i16)(66000/3);
- Use C11 postfix U, L or LL.
U: Unsigned integer L: 32-bits integer LL: 64-bits integer