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

TNS Execution Modes

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

6-15

Basic P Register Operations

Figure 6-8. In Concept, the P Register Controls Execution Flow

Code

Segment

C [0]

C [0]-relative

address of next

instruction to

be executed

Current instruction

being executed

P Register

Initially set by operating system to

C [0]-relative address of first

instruction in program

Instructions are executed in ascending

order unless a nonsequential instruction

(branch, BSUB, PCAL, EXIT, and so on)

is encountered

P Register

1016

C [1015]

C [1016]

C [1021]

1021

BUN +5

Branch

Unconditionally

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