Rainbow-electronics AT89C2051 Bedienungsanleitung PDF herunterladen (Seite 9)

Microcontroller

5-55

Table 3.

Memory Addressing Instructions

Notes: 1. ACC always contains 16 valid bits. All operations are performed in 16-bit precision. 8-bit operands are zero-filled when they

are fetched.

2. SI decrements when data is pushed

3. Data is stored in little endian format.

4. There are no user accessible flags. In the case of CMP, internal flags are maintaned only long enough to accommoate the

LT-UGE instruction.

Name Description (Unused Address Modes)

LD Load ACC 16 bits

LDB Load ACC 8 bits

ADD Add 16 bits

ADDB Add 8 bits

SUB Subtract 16 bits

SUBB Subtract 8 bits

MUL Multiply by 16 bits

MULB Multiply by 8 bits

DIV Divide by 16 bits

DIVB Divide by 8 bits

AND And 16 bits

ANDB And 8 bits

OR OR 16 bits

ORB OR 8 bits

XOR XOR 16 bits

XORB XOR 8 bits

CMP Compare 16 bits (ACC = 1 if equal)

CMPB Compare 8 bits

LDI Load INDEX (16 bits only)

LEAI Load INDEX with address (00, 05)

ST Store ACC 16 bits (00, 05)

STB Store ACC 8 bits (00, 05)

STI Store INDEX (16 bits only) (00, 05)

SHR Shift right (8-bit count only)

SHL Shift left (8-bit count only)

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