Difference between 24 Bit mode and 31 Bit Mode

[ramanaefds]

Hi,

I want to know the details about AMODE and RMODE differences and where we have to use this options. Please let me know these details.

Thanks
Ram.

 

[Dimandja]

Hi ramanaefds,

AMODE and RMODE indicate the memory requirements of a program - how memory should be allocated to accommodate the program. Usually (mainframe), a program will need memory up to 16 Mb (3-bytes addresses are sufficient to hold that kind of maximum value) or above 16 Mb (four-bytes addresses).

AMODE (Addressing Mode) tells the system the type of addressing the program is using (24-bit or 32-bit) - how much memory it can 'reach'.

RMODE (Residency Mode) tells the system where in memory the program should be loaded/located for execution (24-bit - below 16 Mb, 32-bit - above 16 MB).

"...and where we have to use this options." This question needs elaborating, especially since AMODE and RMODE are Assembler language staples.

COBOL programs usually pass 32-bit parameters - accessible from anywhere in memory. A called Assembler program will have to specify AMODE(31) - maximizing its reach - to access them.

Dimandja

 

[Dimandja]

By the way ramanaefds,

Let us know if any responses to the other threads you started were helpful.