NonStop S-Series Server Description Manual (G06.24+)

TNS Instruction Set

HP NonStop S-Series Server Description Manual—520331-003

11-5

Immediate Operand and Shift Instructions

Figure 11-4 presents a comparison of logical (unsigned) shifts and arithmetic (signed)

shifts. In arithmetic left shifts, the sign bit is unaffected (except in accelerated mode);

in logical left shifts, the sign bit participates in the shift. In arithmetic right shifts, the

sign bit is propagated to the right; in logical right shifts, vacated positions are filled with

zeros.

Figure 11-4. Examples of Logical and Arithmetic Shifts

Left Shifts

ALS 3 (Arithmetic left shift three positions)

0101 1 01 000111 001Operand in A:

% 056071

0110 0 00 111001 000Result in A: % 060710

State of sign bit

is preserved

LLS 3 (Logical left shift three positions)

0101 1 01 000111 001Operand in A:

% 056071

1110 0 00 111001 000Result in A: % 160710

Right Shifts

ARS 7 (Arithmetic right shift seven positions)

1111 0 10 110000 001Operand in A: % 171601

1111 1 11 111100 111Result in A:

% 177747

Sign bit is propagated

seven positions

LRS 7 (Logical right shift seven positions)

1111 0 10 110000 001Operand in A:

% 171601

% 000747

0000 0 00 111100 111Result in A:

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