Answer Posted / phil
neither DROP nor USING affect the register contents.
Once a register has been loaded with the address of a piece
of storage, the using statement can be used to 'map' that
storage against a set of labels defining the layout of that
storage e.g. a DSECT. Then whenever one of those labels is
referenced in the code, in moves etc, the assembler resolves
the relative address as a particular displacement from the
absolute address in the register. The DROP instruction
removes the relationship between the labels and the register
and renders subsequent references to those labels as
unresolvable, giving rise to errors at assembly (compile)time.
Typically the DROP instruction will be used to allow use of
the register for another purpose, e.g. address a different
bit of storage via a using staement on second DSECT without
the risk of corrupting that data via moves referencing the
original DSECT.
| Is This Answer Correct ? | 9 Yes | 0 No |
Post New Answer View All Answers
What is need of start 0?
How to pass the parameters from jcl to assembler program?
Ap wkur,=p5 where wkur is a label?
Explain how to access vsam file?
Explain about house keeping in assembler?
Explain the difference in data type "x" and "p"?
What will happen if we drop the base register in the program which contains only one basereg?
What does the following code do? Ap wkur,=p5 where wkur is a label?
Explain how to produce soc7 abend?
what is need of start 0? In steed of
Explain how to initialize a register to 0000?
Explain the difference between various read and find statement and which one should be used when for better adabas performance?
What is maximum displacement and how to cross this limit?
How many maximum base registers we can have in a program?
What is the use of trt instruction?
