HD404849 Datasheet, PDF (110/125 Pages) Hitachi Semiconductor – 4-Bit Single-Chip Microcomputer

HD404849 Series
Memory Register Addressing Mode: The memory registers (MR), which are located in 16 addresses
from $040 to $04F, are accessed with the LAMR and XMRA instructions.
ROM Addressing Modes and the P Instruction
The MCU has four ROM addressing modes, as shown in figure 92 and described below.
[JMPL]
[BRL]
[CALL]
1st word of instruction
2nd word of instruction
Opcode
p₃ p₂ p₁ p₀ d₉ d ₈ d ₇ d ₆ d ₅ d ₄ d₃ d₂ d₁ d₀
Program counter PC₁₃ PC₁₂ PC₁₁ PC₁₀ PC₉ PC₈ PC₇ PC₆ PC₅ PC₄ PC₃ PC₂ PC₁ PC₀
Direct Addressing
Instruction
[BR] Opcode b ₇ b ₆ b ₅ b ₄ b₃ b₂ b₁ b₀
Program counter PC₁₃ PC₁₂ PC₁₁ PC₁₀ PC₉ PC₈ PC₇ PC₆ PC₅ PC₄ PC₃ PC₂ PC₁ PC₀
Current Page Addressing
Instruction
[CAL]
Opcode
d₅ d ₄ d₃ d₂ d₁ d ₀
00 000 0 00
Program counter PC₁₃ PC₁₂ PC₁₁ PC₁₀ PC₉ PC₈ PC₇ PC₆ PC₅ PC₄ PC₃ PC₂ PC₁ PC₀
Zero Page Addressing
[TBR]
Instruction
Opcode
p₃ p₂ p₁ p₀
B register
Accumulator
00
B₃ B₂ B₁ B₀ A₃ A₂ A₁ A₀
Program counter PC₁₃ PC₁₂ PC₁₁ PC₁₀ PC₉ PC₈ PC₇ PC₆ PC₅ PC₄ PC₃ PC₂ PC₁ PC₀
Table Data Addressing
Figure 92 ROM Addressing Modes
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