registers(0-15) ,where they are going be resides., does
that mean here is it resides whether real or virtual
memory? and why?
then why we are assign even registers(0 to 6) for FP
operations????

Answer Posted / steve holton

Clarifications:

As noted, registers are part of the CPU, and --not-- part of
"memory".

There are 16 general purpose registers, which are numbered
0--15 (not 16 - that would be 17 registers!).

There are also other registers - control registers, PSW,
etc., that are used by the operating system, and "normal
mortals" are supposed to ignore...

Floating point registers are separate from the general
purpose registers. Not all floating point instructions
require even registers - if you use 128-bit ("extended
precision") floating point, you can use FPR registers
1,3,5,and 7-15 on ESA390 models that have the AFP registers
"installed".

Is This Answer Correct ?    3 Yes 0 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

Explain how to access vsam file?

607


Explain how to initialize a register to 0000?

585


how do you round the addition or subtraction of two numbers in assembler? what does the following code do? change process tool(code changes from dev to prd) the changes made to your code should be effected in live. How the process takes place. That is how can you move the code changes from development to production?

681


Explain about house keeping in assembler?

632


What is need of start 0?

651






Explain the difference in data type "x" and "p"?

592


how to retrieve the instream data in sysin?

675


Explain how to produce soc7 abend?

632


what is need of start 0? In steed of

669


explain icm instruction?

656


Explain the difference between various read and find statement?

616


In the house keeping section of an MVS assembly language program, like the one below STM R14,R12,12(R13) BASR R12,R0 USING *,R12,R11 LA R11,2048 LA R11,2048(R11,R12) .... .... 1. What if BASR R12,R0 IS NOT PRECEDE USING *,R12,R11? 2. USING (base address), REGISTER does USING directive says assembler to treat particular Register as a base register with the mentioned base address..in the above case * i.e current location counter..well if that is the case why we need BASR R12,R0 ? 3. What if I write like STM R14,R12,12(R13) BASR R12,R0 LA R11,2048 LA R11,2048(R11,R12) USING *,R12,R11 there is no address resolution being calculated in both LA statements so is it a right way to set Base register?..will there be any issues with Domain regarding R11 and R12?

1523


How many maximum base registers we can have in a single program?

631


Explain how to pass instream data in sysin with assembler?

639


explain about maximum displacement and how to cross this limit?

695