UPD705100GJ-100-8 NEC [NEC], UPD705100GJ-100-8 Datasheet - Page 21

• Manufacturer Part Number: UPD705100GJ-100-8
• Description: V830TM 32-BIT MICROCONTROLLER
• Manufacturer: NEC [NEC]

8. REGISTER SETS
8.1 Program Register Set
system register sets which control the state of the V830. The width of all registers is 32 bits.
8.1.1 General-purpose register set
(1) General-purpose registers
The V830 has two types of register sets: general-purpose register sets which can be used by programmers, and
The V830 has 32 general-purpose registers, r0-r31, which can be used either as data registers or address
registers. Note, however, that r0, r30, and r31 contain values that are fixed by hardware or which are used implicitly
by instructions.
(a) Hardware-dependent registers
(b) Software-reserved registers
Hardware-dependent registers contain values that are fixed by hardware or which are used implicitly by
instructions.
These registers are used by assemblers and compilers. To use them as registers for variables, first save
their contents to guard against data loss or damage. When their use is no longer required restore the saved
contents.
r0
r30 : Register reserved for operation
r31 : Link pointer
r1
r2
r3
r4
r5
: Zero register
: Assembler-reserved register
: Handler stack pointer
: Stack pointer
: Global pointer
: Text pointer
Always contains 0.
Serves as an auxiliary register which stores the result of a multiplication or division instruction.
The JAL instruction stores the return address in this register.
Serves as a working register for creating 32 bits of immediate data. It is used implicitly when
the assembler calculates an effective address.
Reserved as the stack pointer for a handler.
Reserved for stack frame creation when a function is called.
Used when accessing a global variable in a data area.
Points to the beginning of a text area.
PD705100
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