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Chapter 6. Macro Processing Language |
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EVAL Function
The MPL processor function EVAL accepts an expression as an argument and returns the decimal character representation of it's result.
The syntax of the EVAL function is:
%EVAL (expression)
The expression arguments must be a legal expression with already defined macro identifiers, if any.
Source text
%SET |
(CNT, 10) |
%' define variable CNT' |
%SET |
(OFS, 20) |
%' define variable OFS' |
MOV |
R15,#%EVAL (%CNT+1) |
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MOV |
WR14,#%EVAL (14+15*200) |
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MOV |
R13,#%EVAL (-(%CNT + %OFS - 1)) |
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MOV |
R2,#%EVAL (%OFS LE %CNT) |
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MOV |
R7,#%EVAL (%OFS GE %CNT) |
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Output text
MOV R15,#11
MOV WR14,#3014
MOV R13,#-29
MOV R2,#0
MOV R7,#1
6
Keil Software — A51/AX51/A251 Macro Assembler and Utilities |
179 |
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Logical Expressions and String Comparison
The following MPL processor functions compare two balanced-text string arguments and return a logical value based on that comparison. If the function evaluates to TRUE, then it returns a value of 1. If the function evaluates to FALSE, then it returns a value of 0. The list of string comparison functions below shows the syntax and describes the type of comparison made for each. Both arguments to these function may contain macro calls. (These MPL calls are expanded before the comparison is made).
%EQS (arg1,arg2) |
True if both arguments are identical |
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%NES (arg1,arg2) |
True if arguments are different in any way |
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%LTS (arg1,arg2) |
True if first argument has a lower value than second |
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argument |
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%LES (arg1,arg2) |
True if first argument has a lower value then second |
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argument or if both arguments are identical |
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%GTS (arg1,arg2) |
True if first argument has a higher value than second |
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argument |
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%GES (arg1,arg2) |
True if first argument has a higher value than second |
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argument or if both arguments are identical |
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Example |
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6 |
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%EQS (A251, A251) |
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0 (FALSE), the space after the comma is part of the |
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second argument |
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LT%S (A251,a251) |
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1 (TRUE), the lower case characters have a higher ASCII |
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value than upper case |
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%GTS (10,16) |
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0 (FALSE), these macros compare strings not numerical |
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values. ASCII '6' is greater than ASCII '1' |
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%GES (a251,a251 ) |
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0 (FALSE), the space at the end of the second argument |
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makes the second argument greater than the first |
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%*DEFINE (VAR1) (A251) |
1 (TRUE) expands to: |
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%*DEFINE (VAR2) (%VAR1) |
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%EQS (%VAR1,%VAR2) %EQS(A251,A251)