C51: ?C? LONG/FLOAT MATH LIBRARY ROUTINES

Information in this article applies to:

• C51 Version 6.x

NOTE

The Keil C51 library includes a number of helper routines for the C51 compiler. These routines perform mundane tasks that are best not included in-line.

These routines are named using the following convention: ?C?ttfff

where:

• tt is the type field,
• and fff is the operation field.

TYPE FIELD

The type field may be one of the follwoing:

• L indicates 2 longs passed in R0/R1/R2/R3 and R4/R5/R6/R7.
• FP indicates 2 floating-pointer numbers (float) passed in R0/R1/R2/R3 and R4/R5/R6/R7.

OPERATION FIELD

The operation field indicates the math operation to perform:

• ADD indicates addition.
• SUB indicates subtraction.
• MUL indicates multiplication.
• DIV indicates division.
• CMP indicates comparison.
• AND indicates bitwise and.
• OR indicates bitwise or.
• XOR indicates bitwise exclusive or.

The results of the operation are returned in R4/R5/R6/R7.

MORE INFORMATION

• Refer to Floating-point Numbers in the Cx51 User's Guide.

SEE ALSO

• C51: ?C? LIBRARY ROUTINES
• C51: ?C? LOAD AND STORE LIBRARY ROUTINES
• C51: SUPPORT FOR FLOATING-POINT NUMBERS
• C51: USE OF F0 AND F1 IN PSW
• C51: DOES THE RUN-TIME LIBRARY DISABLE INTERRUPTS?
• C51: STACK REQUIREMENTS OF RUN-TIME LIBRARY FUNCTIONS

FORUM THREADS

The following Discussion Forum threads may provide information related to this topic.

• turn off the optimizer

Last Reviewed: Friday, July 15, 2005