28 lines
769 B
Plaintext
28 lines
769 B
Plaintext
PDP-10 Instruction Format
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PDP-10 machine code instructions are stored in 36-bit words with the
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following format:
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Bits Length Contents
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0-8 9 OP: operation code
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9-12 4 AC: accumulator
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13 1 I: indirect flag
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14-17 4 X: index
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18-35 18 Y: address
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(Input/output instructions have a different format, but are only allowed
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in privileged programs.)
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Instruction fields are represented in assembly language statements as
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follows:
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OM (AC, I, Y, X are zero)
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OM Y (AC, I, X are zero)
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OM AC, (I, Y, X are zero)
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OM AC,Y (I and X are zero)
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OM AC,Y(X) (I is zero)
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OM AC,@Y (I is 1, X is zero)
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OM AC,@Y(X) (AC, I, Y, X all non-zero)
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(OM: operation code mnemonic name) |