uPD789074 Subseries 8-Bit Single-Chip Microcontrollers UD - Home

CHAPTER 3 CPU ARCHITECTURE3.2.2 General-purpose registersThe general-purpose registers consist of eight 8-bit registers (X, A, C, B, E, D, L, and H).In addition to each register being used as an 8-bit register, two 8-bit registers can be used in pairs as a 16-bitregister (AX, BC, DE, and HL).Registers can be described in terms of function names (X, A, C, B, E, D, L, H, AX, BC, DE, and HL) and absolutenames (R0 to R7 and RP0 to RP3).Figure 3-14. General-Purpose Register Configuration(a) Absolute names16-bit processingRP3RP2RP1RP08-bit processingR7R6R5R4R3R2R1R015 0 7 0(b) Function names16-bit processingHLDEBCAX8-bit processingHLDEBCAX15 0 7 0User’s Manual U14801EJ3V1UD 49