ST ST7 - Page 161

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6 - STMicroelectronics Programming Tools
95 001F B602 ld A, NbOfApples
95 0021 BB03 add A, NbOfPears
95 0023 #IFB NbOfFruit
95 0023 B704 ld NbOfFruit, A ; result in third argument
95 0025 #ENDIF
96 0025
97
98 Addition NbOfApples, NbOfFruit,
98 0025 B602 ld A, NbOfApples
98 0027 BB04 add A, NbOfFruit
98 0029 #IFB
98 0029 B704 ld NbOfFruit, A ; result in second argument
98 002B #ELSE
#IFLAB <identifier> Conditional.
This conditional tests whether an argument is a label. This may be used to distinguish be-
tween a label and a constant. For example, let us consider again the addition macro, but
changed so that the first two arguments may be at will either labels or constants. The third ar-
gument must be a label. The macro is:
AddFlex MACRO argA, argB, Result
#IFLAB argA
ld A, argA
#ELSE
ld A, #argA ; 1st arg is constant
#ENDIF
#IFLAB argB
add A, argB
#ELSE
add A, #argB ; 2nd arg is constant
#ENDIF
ld Result, A
MEND
We see that according to whether the argument is a label or not , a different addressing mode
is used (extended or immediate). Here are two expansions with different arrangements of ar-
guments:
115 AddFlex NbOfApples, 3, NbOfFruit
115 002D #IFLAB NbOfApples
115 002D B602 ld A, NbOfApples
115 002F #ELSE
115 002F #IFLAB 3
115 002F AB03 add A, #3 ; 2nd arg is constant
115 0031 #ENDIF
115 0031 B704 ld NbOfFruit, A
116 0033
117 AddFlex 3, NbOfApples, NbOfFruit