RL78/F13, F14 CHAPTER 3 CPU ARCHITECTURE
R01UH0368EJ0210 Rev.2.10 143
Dec 10, 2015
3.2.2 General-purpose registers
General-purpose registers are mapped at particular addresses (FFEE0H to FFEFFH) of the data memory. The general-
purpose registers consists of 4 banks, each bank consisting of eight 8-bit registers (X, A, C, B, E, D, L, and H).
Each register can be used as an 8-bit register, and two 8-bit registers can also be used in a pair as a 16-bit register (AX,
BC, DE, and HL).
These registers can be described in terms of function names (X, A, C, B, E, D, L, H, AX, BC, DE, and HL) and absolute
names (R0 to R7 and RP0 to RP3).
Register banks to be used for instruction execution are set by the CPU control instruction (SEL RBn). Because of the 4-
register bank configuration, an efficient program can be created by switching between a register for normal processing and
a register for interrupts for each bank.
Caution It is prohibited to use the general-purpose register (FFEE0H to FFEFFH) space for fetching
instructions or as a stack area.
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