P60ARM-B Zarlink Semiconductor, Inc., P60ARM-B Datasheet - Page 67

• Manufacturer Part Number: P60ARM-B
• Description: 32-bit RISC microprocessor
• Manufacturer: Zarlink Semiconductor, Inc.

(4)
(5)
(6)
This is not quite optimal, but close. An example of its non-optimality is multiply by 45 which is done by:
rather than by:
(a)
(b)
(c)
Multiplication by 6
ADD
MOV
Multiply by 10 and add in extra number
ADD
ADD
General recursive method for Rb := Ra*C, C a constant:
If C even, say C = 2^n*D, D odd:
D=1:
D<>1:
If C MOD 4 = 1, say C = 2^n*D+1, D odd, n>1:
D=1:
D<>1:
If C MOD 4 = 3, say C = 2^n*D-1, D odd, n>1:
D=1:
D<>1:
RSB
RSB
ADD
ADD
ADD
Ra,Ra,Ra,LSL #1
Ra,Ra,LSL#1
Ra,Ra,Ra,LSL#2
Ra,Rc,Ra,LSL#1
MOV
{Rb := Ra*D}
MOV
ADD
{Rb := Ra*D}
ADD
RSB
{Rb := Ra*D}
RSB
Rb,Ra,Ra,LSL#2
Rb,Ra,Rb,LSL#2
Rb,Ra,Rb,LSL# 2
Rb,Ra,Ra,LSL#3
Rb,Rb,Rb,LSL#2
Rb,Ra,LSL #n
Rb,Ra,Ra,LSL #n
Rb,Ra,Ra,LSL #n
Rb,Rb,LSL #n
Rb,Ra,Rb,LSL #n
Rb,Ra,Rb,LSL #n
; multiply by 3
; and then by 2
; multiply by 5
; multiply by 2 and add in next digit
; multiply by 3
; multiply by 4*3-1 = 11
; multiply by 4*11+1 = 45
; multiply by 9
; multiply by 5*9 = 45
Instruction Set - Examples
63