Maxim Integrated MAXQ Family - Manual (Page 211)

MAXQ Family User’s Guide
(MAXQ20 Version) Shift Accumulator Right/
SR/SRA/SRA2/SRA4 Shift Accumulator Right Arithmetically
One, Two, or Four Times
Description: Shifts the active accumulator right once for the SR, SRA instructions and 2 or 4 times, respectively, for the SRA2,
SRA4 instructions. The SR instruction shifts a 0 into the accumulator msb while the SRA, SRA2, and SRA4 instruc-
tions effectively shift a copy of the current msb into the accumulator, thereby preserving any sign orientation. For
each shift iteration, the accumulator lsb is shifted into the Carry (C) flag.
Status Flags: C, S (changes for SR only), Z
SR Operation: 15 Active Accumulator (Acc) 0 Carry Flag
Acc.15 ← 0; Acc.[14:0]← Acc.[15:1]; C ← Acc.0
Encoding: 15 0
Example(s): ; Acc = A345h, C=1, S=1, Z=0
SR ; Acc = 51A2h, C=1, S=0, Z=0
SR ; Acc = 28D1h, C=0, S=0, Z=0
SRA Operation: 15 Active Accumulator (Acc) 0 Carry Flag
Acc.[14:0] ← Acc.[15:1]
Acc.15 ← Acc.15
C ← Acc.0
Encoding: 15 0
Example(s): ; Acc = 0003h, C=0, Z=0
SRA ; Acc = 0001h, C=1, Z=0
SRA ; Acc = 0000h, C=1, Z=1
1000 1010 1010 1010
1000 1010 1111 1010
0
Maxim Integrated 18-34