UPD784938 Datasheet, PDF (96/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 3 CPU ARCHITECTURE
In addition to the function name that emphasizes the specific function of the register (X, A, C, B, E, D, L, H, AX, BC, VP, UP,
DE, HL, VVP, UUP, TDE, WHL), each register can also be described by its absolute name (R0 to R15, RP0 to RP7, RG4 to RG7).
The correspondence between these names is shown in Table 3-5.
Table 3-5. Correspondence between Function Names and Absolute Names
(a) 8-bit registers
Absolute Name
R0
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
R11
R12
R13
R14
R15
Function Name
RSS = 0
RSS = 1^Note
X
A
C
B
X
A
C
B
E
E
D
D
L
L
H
H
(b) 16-bit registers
Absolute Name
RP0
RP1
RP2
RP3
RP4
RP5
RP6
RP7
(c) 24-bit registers
Absolute Name
RG4
RG5
RG6
RG7
Note RSS should only be set to 1 when a 78K/III Series program is used.
Function Name
RSS = 0
RSS = 1^Note
AX
BC
AX
BC
VP
VP
UP
UP
DE
DE
HL
HL
Function Name
VVP
UUP
TDE
WHL
Remark R8 to R11 have no function name.
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Preliminary User’s Manual U13987EJ1V0UM00