HLA provides two special conditional jump instructions: jt
( jump if true) and jf
( jump if false). These instructions take the following syntax:
jt(boolean_expression
)target_label
; jf(boolean_expression
)target_label
;
The boolean_expression
is the standard HLA boolean expression allowed by if..endif
and other HLA high-level language statements. These instructions evaluate the boolean expression and jump to the specified label if the expression evaluates true (jt
) or false (jf
).
These are not real 80x86 instructions. HLA compiles them into a sequence of one or more 80x86 machine instructions that achieve the same result. In general, you should not use these two instructions in your main code; they offer few benefits over using an if..endif
statement and they are no more readable than the pure assembly language sequences they compile into. HLA provides these "medium-level" instructions so that you may create your own high-level control structures using macros (see Chapter 9 and the HLA reference manual for more details).