**Operation:**

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Destination (base 10) - Source(base 10) -->; Destination

**Assembler Syntax:**

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ABCD Dx, Dy

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ABCD -(Ax), -(Ay)

**Attributes:** Size = (Byte)

**Description:** Subtracts the source operand from the destination

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operand and stores the result in the destination location.

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The subtraction is performed using binary coded decimal

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arithmetic. The operands, which are packed BCD numbers,

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can be addressed in two different ways:

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1. Data register to data register (Data Register Direct).

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2. Memory to memory (Pre-decrement).

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This operation is a byte operation only.

**Condition Codes:**

\c24242

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X Set the same as the carry bit.

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N Undefined.

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Z Cleared if the result is nonzero. Unchanged otherwise.

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V Undefined.

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C Set if a decimal carry was generated. Cleared otherwise.

Note: Normally the Z condition code bit is set via programming before

the start of an operation. This allows successful tests for zero results

upon completion of multiple-precision operations.