Analog Devices adsp-2100 Manual page 349

ALU
15
SUBTRACT Y-X / SUBTRACT Y-X with BORROW
AV
AC
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
AMF specifies the ALU or MAC operation. In this case,
AMF = 11010 for yop – xop + C – 1
AMF = 11001 for yop – xop
(Note that –xop + C – 1 is a special case of yop – xop + C – 1 with yop=0.)
Z:
Xop:
(–xop + constant) Conditional ALU/MAC operation, Instruction Type 9:
(ADSP-217x, ADSP-218x, ADSP-21msp58/59 only)
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
AMF specifies the ALU or MAC operation, in this case:
AMF = 11010 for constant – xop + C – 1
AMF = 11001 for constant – xop
Z:
Xop:
BO, CC, and YY specify the constant (see Appendix A, Instruction Coding).
15 – 26
Set if an arithmetic overflow occurs. Cleared otherwise.
Set if a carry is generated. Cleared otherwise.
1 0 0 Z AMF
Destination register
X operand
1 0 0 Z AMF
Destination register
X operand
Yop Xop 0 0 0 0
Yop: Y operand
COND: condition
YY Xop
COND: condition
COND
CC BO COND