SS Instructions

• have 2 D(B) operands

• 6 byte instructions

• 3 encoding formats

• Format: label MVC D₁(L,B₁),D₂(B₂)

• Moves L bytes from D₂(B₂) to D₁(B₁)

• L is decimal number between 0 and 256

    MVC 0(8,R10),0(R4) ==> moves 8 bytes from 0(R4) to 0(R10)

    MVC NUM1(6),BUFFER ==> moves 6 bytes from BUFFER to NUM1

• Format: label CLC D₁(L,B₁),D₂(B₂)

• Compares L EBCDIC bytes at D₁(B₁) with L EBCDIC bytes at D₂(B₂) one byte at a time

• L is decimal number between 0 and 256

• Should be used for characters

• Sets Condition code

  Code     Meaning
   0       Equality
   1       first operand < second operand
   2       first operand > second operand
  

    NUM1 DC F‘10’
    NUM2 DC F‘5’

    L R3,NUM1
    C R3,NUM2

    RESULT: NUM1 is greater than NUM2

    CLC NUM1(4),NUM2

    RESULT: NUM1 is less than NUM2.

    Will work in this example since 0A is greater than 05

    What if NUM2 DC F‘-5’?

    RESULT: will not work because 00 is less than FF