Motorola 68000 - Page 52

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The 68000's Instruction Set
RTS Return from subroutine
Operation: [PC] ← [M([SP])]; [SP] ← [SP] + 4
Syntax: RTS
Attributes: Unsized
Description: The program counter is pulled from the stack and the previous
value of the PC is lost. RTS is used to terminate a subroutine.
Condition codes: X N Z V C
- - - - -
SBCD Subtract decimal with extend
Operation: [destination]
10
← [destination]
10
- [source]
10
- [X]
Syntax: SBCD Dy,Dx
SBCD -(Ay),-(Ax)
Attributes: Size = byte
Description: Subtract the source operand from the destination operand together
with the X-bit, and store the result in the destination. Subtraction
is performed using BCD arithmetic. The only legal addressing
modes are data register direct and memory to memory with
address register indirect using auto-decrementing.
Condition codes: X N Z V C
* U * U *
Z: Cleared if result is non-zero. Unchanged otherwise. The Z-bit
can be used to test for zero after a chain of multiple precision
operations.
Scc Set according to condition cc
Operation: IF cc = 1 THEN [destination] ← 11111111
2
ELSE [destination] ← 00000000
2
Syntax: Scc <ea>