Assembler MVC Instruction

srishyla_ks · New User Joined: 07 Jun 2005 Posts: 3

Hi, can anyone please tell me, why MVC insruction can move a maximum of 256 byte data

thanks in advance

jon_s_rice · Posted: Thu Dec 22, 2005 4:47 pm Post subject:

The length of the field is contained in a single byte of the instruction.

KMK · New User Joined: 29 Jul 2005 Posts: 18

Hi,

To be more precise MVC instruction is of SS format

MVC D1(L,B1),D2(B2)
ie bit position are as follows

D1 0 - 8

L 9 - 16

B1 17 - 20

D1 21- 32

B2 33 - 36

D2 37 - 47

Where L ie length occupies only 8 bits hence 2 power 8 = 256 it can hold.
Hence we can move only data of length 256.

ap_mainframes · Posted: Thu Dec 29, 2005 8:57 am Post subject: Re: Assembler MVC Instruction

Hi,
MVC is a SS type of instruction and in these type of instructions Length is of 1 byte.So the maximum FF can be accomodated hence the operation carried out can have a limit of 256 bytes.
Hope this answers.