Holtek HT-IDE, Руководство пользователя, Страница: 122 / 258

Initial value
Global variables cannot be initialized when declared. Local variables do not
have this constraint. Constant variables must be initialized when declared.
For example:
unsigned int i1= 0; //illegal declaration; can not be
//initialized
unsigned int i2;
const unsigned int i3; //illegal declaration; should be
//initialized
const unsigned int i4=5;
const char a1[5]; //illegal declaration; should be
//initialized
const char a2[5]={0
×
1,0
×
2,0
×
3,0
×
4,0
×
5};
const char a3[]="abcde";
Multiply/Divide/Modulus
The multiply, divide and modulus (’*’, ’/’, ’%’) operators are implemented by
system calls. It is necessary to include the math.lib library if these arith-
metical operators are used. To include a library, select [options] in the main
menu, select [project...], put the library name in the [libraries] field.
Stack
Because the Holtek HT48CX0 microcontrollers have from 2 to 8 stacks the
programmer needs to consider the function call depth to avoid stack over-
flow. The multiply, divide and modulus of the Holtek C language are
implemented by "call" instructions, taking one stack. The input/output port
system functions are implemented without "call" instructions.
Operator/System Function Stack Needed
main ( ) 0
* 1
/ 1
% 1
peekPX(), X=A,B,C,D,E,F,G 0
peekPXC(), X=A,B,C,D,E,F,G 0
pokePX(), X=A,B,C,D,E,F,G 0
pokePXC(), X=A,B,C,D,E,F,G 0
setPX(), X=A,B,C,D,E,F,G 0
setPXi(), i=0,1,2,3,4,5,6,7 and X=A,B,C,D,E,F,G 0
setPXC(), X=A,B,C,D,E,F,G 0
HT-IDE User’s Guide
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