Digi NS9215 - Manual (Page 82)

W O R K I N G W I T H T H E C P U
Instruction sets
82 Hardware Reference NS9215
Arm926EJ-S
process block
diagram
This drawing shows the main blocks in the ARM926EJ-S processor.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I n s t r u c t i o n s e t s
The processor executes three instruction sets:
32-bit ARM instruction set
16-bit Thumb instruction set
8-bit Java instruction set
ARM instruction
set
The ARM instruction set allows a program to achieve maximum performance with
the minimum number of instructions. The majority of instructions are executed in a
single cycle.
Thumb
instruction set
The Thumb instruction set is simpler than the ARM instruction set, and offers
increased code density for code that does not require maximum performance. Code
can switch between ARM and Thumb instruction sets on any procedure call.
DEXT
Write buffer
DCACHE
Cache
PA
TAGRAM
writeback
write
buffer
MMU
TLB ARM926EJ-S
IROUTE
DROUTE
FCSE
WDATA RDATA
INSTR
ICACHE
IEXT
Bus
interface
unit
Data
AHB
interface
Instruction
AHB
interface
AHB
AHB
DA
IA
DMVA
IMVA