Z8
®
CPU
User Manual
UM001604-0108 Instruction Description
240
Swap Nibbles
Syntax
SWAP dst
Instruction Format
Operation
dst(7-4) ↔ dst(3-0)
The contents of the lower four bits and upper four bits of the destination operand are
swapped.
Address modes R or IR can be used to specify a 4-bit Working Register. In this format, des-
tination Working Register operand is specified by adding
1110b (Eh) to the high nibble of
the operand. For example, if Working Register
R12 (CH) is the destination operand, then
ECh is used as the destination operand in the Op Code.
Example 1
If Register BCh contains B3h (10110011B), the statement:
SWAP B3h
Op Code: F0 B3
leaves the value 3Bh (00111011B) in Register BCh. The Z and S Flags are cleared.
Cycles
OPC
(Hex)
Address Mode
dst
OPC dst
6F0 R
6F1 IR
Flag Description
C Unaffected
Z Set if the result is zero; cleared otherwise.
S Set if the result bit 7 is set; cleared otherwise.
V Undefined
D Unaffected
H Unaffected
Edst
Note:
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