Maxim Integrated MAXQ Family - Manual (Page 209)

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MAXQ Family User’s Guide
(MAXQ10 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 two or four 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: 7 Active Acc (Acc) 0 Carry Flag
Acc.[6:0] ← Acc.[7:1]
Acc.7 ← 0
C ← Acc.0
Encoding: 15 0
Example(s): ; Acc = 45h, C=1, S=0, Z=0
SR ; Acc = 22h, C=1, S=0, Z=0
SR ; Acc = 11h, C=0, S=0, Z=0
SRA Operation: 7 Active Acc (Acc) 0 Carry Flag
Acc.[6:0] ← Acc.[7:1]
Acc.7 ← Acc.7
C ← Acc.0
Encoding: 15 0
Example(s): ; Acc = 03h, C=0, Z=0
SRA ; Acc = 01h, C=1, Z=0
SRA ; Acc = 00h, C=1, Z=1
0
1000 1010 1010 1010
1000 1010 1111 1010
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