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15 – 33
Z: Destination register COND: condition
Xop: X operand
BO, CC, and YY specify the constant (see Appendix A, Instruction Coding).
Syntax: [ IF cond ] AR = – xop ;
AF yop
Permissible xops Permissible yops Permissible conds (see Table 15.9)
AX0 MR2 AY0 EQ LE AC
AX1 MR1 AY1 NE NEG NOT AC
AR MR0 AF GT POS MV
SR1 GE AV NOT MV
SR0 LT NOT AV NOT CE
Example: IF LT AR = – AY0;
Description: Test the optional condition and if true, then NEGATE the
source operand and store in the destination location. If the condition is not
true then perform a no-operation. Omitting the condition performs the
NEGATE operation unconditionally. The source operand is contained in
the data register specified in the instruction.
Status Generated:
ASTAT: 7 6 543210
SS MV AQ AS AC AV AN AZ
––– – * ** *
AZ Set if the result equals zero. Cleared otherwise.
AN Set if the result is negative. Cleared otherwise.
AV Set if operand = H#8000. Cleared otherwise.
AC Set if operand equals zero. Cleared otherwise.
Instruction Format:
Conditional ALU/MAC Operation, Instruction Type 9:
23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 0 1 0 0 Z AMF Yop Xop 0 0 0 0 COND
AMF specifies the ALU or MAC operation. In this case,
AMF = 10101 for –yop operation.
AMF = 11001 for –xop operation
ALU
NEGATE
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