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PACK

PACK. PACK. Instruction type: SS2 Explicit Coding: D1(L1,B1),D2(L2,B2) Example PACK 3(4,5),8(9,7) Example PACK X(3),Y(4) Use: Converts zoned decimal fields to packed, (also works on character fields that only contain digits). What does it do?. PACK X,Y.

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PACK

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  1. PACK

  2. PACK • Instruction type: SS2 • Explicit Coding: D1(L1,B1),D2(L2,B2) • Example PACK 3(4,5),8(9,7) • Example PACK X(3),Y(4) • Use: Converts zoned decimal fields to packed, (also works on character fields that only contain digits)

  3. What does it do? PACK X,Y F1 F2 F3 F4 F5 C6 Y 00 00 01 23 45 6C X

  4. What does it do? PACK X,Y F1 F2 F3 F4 F5 C6 Y 45 6C X

  5. PACK • Example use: Assume: X DS PL5 Y DC Z’-234.57’ You execute: PACK X,Y Y Before: F2F3F4F5D7 X After: 000023457D

  6. PACK • Example use: Assume: X DS PL2 (TOO SHORT) Y DC Z’-234.57’ You execute: PACK X,Y Y Before: F2F3F4F5D7 X After: 457D DIGITS TRUNCATED

  7. Programming Tips • Make sure the receiving field will hold the result • Pack works no matter the state of the data. In other words, if you pack garbage, you get more garbage • Pack doesn’t generate a data exception (SOC7) • You won’t discover the data is bad until you do arithmetic – AP, SP, MP, …

  8. Try it in VisibleZ • Try the following programs: • pack.obj • pack1.obj • pack2.obj • pack3.obj • pack4.obj

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