| ||||
| Home Products Download Events Support | ||||
Technical Support
On-Line Manuals
AARM User's Guide
AARM Introduction Assembling Programs Operators Control Statements 
Macro Processor Standard Macro Processor 
Standard Macro Controls Defining Standard Macros Calling Standard Macros Local Symbols Exiting A Macro Built-in Macros REPT IRP IRPC Standard Macro Operators NUL Operator & Operator % Operator ;; Operator ! Operator C Preprocessor Exceptions Side-Effects Predefined Macros Examples Error Messages% Operator
The percent operator ('%') is used to pass the value of an expression to a macro rather than passing the literal expression itself. The following example shows a macro definition, that requires a numeric value, along with macro invocations that use the percent operator to pass the value of an expression to the macro.
OUTPORT MACRO N
MOV R1, #N
ENDM
RESET_SIG EQU 0FFh
CLEAR_SIG EQU 0
OUTPORT %(RESET_SIG AND NOT 11110000b)
; Expands into MOV R1, #15
OUTPORT %(CLEAR_SIG OR 11110000b)
; Expands into MOV R1, #240
The expressions evaluated in the highlighted lines could not be passed to the macro because the macro expects a numeric value. Expressions like these must be evaluated before the macro. The percent operator forces the assembler to generate a numeric value which is then passed to the macro.
| Contact Site Map Press Privacy | Copyright © 2012 ARM Ltd and ARM Germany GmbH. All rights reserved. |
