MODAL instructions

[kingo]

Hi all,

I am reading about SI Instructions that Operands like MVC and CLC and tried to make program fail by passing values of length larger than 256 and smaller than 0.

I understand there are OPERANDS MVCL and CLCL or CLCLE which supports for larger data , Does these operands work only on certain modes 24,31,64?

Also is there any cheat cheat like ADDRESS MODE + OPERANDS supported and type of instruction if its SI,RX,RR,SS ?

Thanks.

[Robert Sample]

I am reading about SI Instructions that Operands like MVC and CLC and tried to make program fail by passing values of length larger than 256 and smaller than 0.

Good luck with this quest. The instructions generate a single byte for the length, and that byte can range in value from X'00' to X'FF' -- 0 to 255 in decimal. The byte is unsigned, so you CANNOT have values less than zero -- period. And since the length - 1 is stored in that byte, the range of values is 1 to 256 -- period.

24-bit, 31-bit, 64-bit mode do not impact instructions -- MVC is move character no matter the addressing mode. However, 64-bit mode adds new instructions (grande due to a G being added to the instruction) to manipulate 64-bit addresses since the memory management and memory processing for 64-bit addresses is decidedly different than for 24-bit or 31-bit addresses. You do need to be aware of addressing, though, as you cannot (successfully) access a 31-bit address when your program is running in 24-bit address mode.

Also is there any cheat cheat

Assuming you mean "cheat sheet" instead of "cheat cheat", there probably is -- Google will help you find one. Googling rx, si instructions returned about 2,200,000 hits for me and several on the first page of results could be considered "cheat sheets".

[kingo]

Hi Robert,

Yes, I am trying to learn with assemble listing with it really helps to do with that with instructions format. I am so loving this now

Yes I meant cheat sheat... As you said I got it...

360 Instructions

Thanks again