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Chapter 5 CPU Registers
1.General-purpose Registers
Chapter 5 CPU Registers
1. General-purpose Registers
Registers R0 through R15 are general-purpose registers. These registers are used for accumulator and
memory access pointers on various operations.
Figure 1-1 General-purpose Registers
Of 16 registers, the following registers are reserved for special application.
• R13: Virtual accumulator
• R14: Frame pointer
• R15: Stack pointer
Initial values by reset are indeterminate for R0 through R14. Initial value by reset is 00000000
H
(SSP value)
for R15.
2. Dedicated Registers
Dedicated registers consist of program counter (PC), program status (PS), table-base register (TBR), return
pointer (RP), system stack pointer (SSP), user stack pointer (USP) and multiply & divide register (MDH/MDL).
Figure 2-1 Dedicated Registers List
XXXX XXXX
H
XXXX XXXX
H
...
...
...
...
0000 0000
H
AC
FP
SP
R0
R1
R12
R13
R14
R15
...
...
...
...
32 bit
[Initial value]
Program counter
Program status
Table-base register
Return pointer
System stack pointer
User stack pointer
Multiply & divide register