Accelerator Manual (G06.24+, H06.03+)

Introduction
Accelerator Manual—527303-002
1-2
How the Accelerator Works
Accelerator option settings, but these actions are worthwhile only in the case of
performance-critical programs.
Figure 1-2, User Program Execution Modes on TNS/R Systems, on page 1-2 shows
two of the execution modes available to user programs on TNS/R systems: TNS mode
and accelerated mode.
•
TNS mode is the operational environment in which TNS instructions execute. On
TNS/R systems, TNS instructions are implemented by millicode routines.
•
Accelerated mode is the operational environment in which RISC instructions
generated by the Accelerator execute. On TNS/R systems, RISC instructions
execute directly on the RISC processor.
The Accelerator runs on both TNS and TNS/R systems, and produces the same output
in both environments: a file containing both the original TNS code and its RISC code
equivalent. Accelerated object files can run on both TNS and TNS/R systems, although
TNS systems ignore the RISC code.
Figure 1-2. User Program Execution Modes on TNS/R Systems
VST0102.vdd
TNS Object File
TNS
Object Code
Accelerated Object File
TNS
Object Code
Accelerated
Object Code
TNS
Instructions
TNS
Instructions
RISC
Instructions
RISC
Instructions
Millicode
TNS/R Processor