1989_MELPS_7700_Software_Manual

Instructions
4.1.2 Arithmetic Instructions
The arithmetic instructions perform addition, subtraction, multiplication, division, logical operation,
comparison, rotation and shifting of register and memory contents.
The following table summarizes the arithmetic instructions supported:
Category Instruction Description
Addition ADC Adds the contents of the accumulator,the contents of memory and
Subtraction
the contents of the carry flag.
Multiplication
SBC
Subtracts the complements of the contents of memory and carry
flag from the contents of the accumulator.
Division
INC Increments the accumulator or memory contents by 1.
DEC Decrements the accumulator or memory contents by 1.
INX Increments the contents of the index register X by 1.
DEX Decrements the contents of the index register X by 1.
INY Increments the contents of the index register Y by 1.
DEY Decrements the contents of the index register Y by 1.
MPY
DIV
Multiples the contents of the accumulator A and the contents of
memory.
Divides the numeric value whose lower byte is the contents of the
accumulator A and upper byte is the contents of the accumulator B
by the contents of memory.
Logical operation AND Performs logical AND between the contents of the accumu·
lator and the contents of memory.
ORA
EaR
Performs logical OR between the contents of the accumulator and
the contents of memory.
Performs logical exclusive-OR between the contents of the accumulator
and the contents of memory.
Comparison CMP Compares the contents of the accumulator with the contents of
memory.
CPX
CPY
Compares the contents of the index register X and the contents of
memory.
Compares the contents of the index register Y and the contents of
memory.
Shifting, Lotation ASL Shifts the contents of the accumulator or memory to the left by 1 bit.
LSR Shifts the contents of the accumulator or memory to the right by 1
bit.
ROL
ROR
RLA
Links the contents of accumulator or memory with the carry flag,
and rotates the result to the left by 1 bit.
Links the contents of accumulator or memory with the carry flag,
and rotates the result to the right by 1 bit.
Rotates the contents of the accumulator A to the left by the specified
number of bits.
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