Maxim Integrated MAXQ622 - Manual (Page 45)

MAXQ612/MAXQ622 User’s Guide
Maxim Integrated 3-9
• Increment modulo 8: AP = AP[3] + ((AP[2:0] + 1) mod 8)
• Decrement modulo 8: AP = AP[3] + ((AP[2:0] - 1) mod 8)
• Increment modulo 16: AP = (AP + 1) mod 16
• Decrement modulo 16: AP = (AP - 1) mod 16
For this example, assume that all 16 accumulator registers are initially set to zero .
move AP, #02h ; select A[2] as active accumulator
mov APC, #02h ; auto-increment AP[1:0] modulo 4
; AP A[0] A[1] A[2] A[3]
; 02 0000 0000 0000 0000
add #01h ; 03 0000 0000 0001 0000
add #02h ; 00 0000 0000 0001 0002
add #03h ; 01 0003 0000 0001 0002
add #04h ; 02 0003 0004 0001 0002
add #05h ; 03 0003 0004 0006 0002
3.5.3 ALU Operations Using the Active Accumulator and a Source
The following arithmetic and logical operations can use any register or immediate value as a source . The active accu-
mulator, Acc, is always used as the second operand and the implicit destination . Also, Acc cannot be used as the
source for any of these operations .
add A[4] ; Acc = Acc + A[4]
addc #32h ; Acc = Acc + 0032h + Carry
sub A[15] ; Acc = Acc – A[15]
subb A[1] ; Acc = Acc – A[1] - Carry
cmp #00h ; If (Acc == 0000h), set Equals flag
and A[0] ; Acc = Acc AND A[0]
or #55h ; Acc = Acc OR #0055h
xor A[1] ; Acc = Acc XOR A[1]
3.5.4 ALU Operations Using Only the Active Accumulator
The following arithmetic and logical operations operate only on the active accumulator .
cpl ; Acc = NOT Acc
neg ; Acc = (NOT Acc) + 1
rl ; Rotate accumulator left (not using Carry)
rlc ; Rotate accumulator left through Carry
rr ; Rotate accumulator right (not using Carry)
rrc ; Rotate accumulator right through Carry
sla ; Shift accumulator left arithmetically once
sla2 ; Shift accumulator left arithmetically twice
sla4 ; Shift accumulator left arithmetically 4 times
sr ; Shift accumulator right, set Carry to Acc.0,
; set Acc.15 to zero