Register-Register Transfer Form

on System

Fetch and Decoding (Default)

MAR = PC
memoryRead()
IR = MDR

LDA (1__)

MAR = ADDR
memoryRead()
A = MDR

STA (2__)

MAR = ADDR
MDR = A
memoryWrite()

ADDA (3__)

MAR = ADDR
memoryRead()
A = alu('+', A, MDR)

SUBA (4__)

MAR = ADDR
memoryRead()
A = alu('-', A, MDR)

SKZ (511)

#$ programStatus("Z")
#$= true
PC = PC + 1

SKP (512)

#$ (not programStatus("S")) and (not programStatus("Z"))
#$= true
PC = PC + 1

SKN (513)

#$ (programStatus("S")) and (not programStatus("Z"))
#$= true
PC = PC + 1

JMP (6__)

#! handcounter false
PC = ADDR

SWAPAX (505)

swapReg(A, X)

LDA #IMMED (52_)

A = IMMED

ADDA #IMMED (53_)

A = alu('+', A, IMMED)

SUBA #IMMED (54_)

A = alu('-', A, IMMED)

ADDA *ADDR (7__)

MAR = ADDR
memoryRead()
MAR = MDR
memoryRead()
A = alu('+', A, MDR)

ADDA @ADDR (8__)

MAR = ADDR + X
memoryRead()
A = alu('+', A, MDR)