How to access array elemnts in assembler

kalpana · New User Joined: 19 Nov 2004 Posts: 24 Location: Banglore

can any one please answer to these below instruction questions?

1) How to pass paramters to the sub program? How it will be recieved by calling program? How the control is sent back to called program?
2)How to access array elemnts in assembler?
3)How to suppress leading zeros using edit instruction?

Many thanks in advance
Kalpana

Robert Sample · Posted: Fri Jul 18, 2008 8:05 pm

I am not an Assembler expert, but:
1. Set up an address block in memory. The first parameter's address goes at offset 0, the second parameter's address goes at offset 4, etc. The last address has the high-order bit set to '1' to indicate the end of the list. Load the address of block into register 1. The called program uses register 1 to load the parameter addresses. Under standard register conventions, register 14 contains the return address upon entry into the subroutine.
2. Trick question. There's no such thing as arrays, per se, in Assembler. All Assembler instructions use offsets from registers to determine addresses.
3. Look into the ED or EDMK instructions.

kalpana · New User Joined: 19 Nov 2004 Posts: 24 Location: Banglore

can you please explain me with sample code for sub program concept.

and array elements accessing