UPSD3212A(2009) Просмотр технического описания (PDF) - STMicroelectronics

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UPSD3212A
(Rev.:2009)

Flash programmable system devices with 8032 MCU and USB and programmable logic

STMicroelectronics 

UPSD3212A, UPSD3212C, UPSD3212CV

Architecture overview

2.9

Note:

Note:

Arithmetic instructions

The arithmetic instructions is listed in Table 4. The table indicates the addressing modes

that can be used with each instruction to access the <byte> operand. For example, the ADD

A, <byte> instruction can be written as:

ADD a, 7FH (direct addressing)

ADD A, @R0 (indirect addressing)

ADD a, R7 (register addressing)

ADD A, #127 (immediate constant)

Any byte in the internal Data Memory space can be incremented without going through the

Accumulator.

One of the INC instructions operates on the 16-bit Data Pointer. The Data Pointer is used to

generate 16-bit addresses for external memory, so being able to increment it in one 16-bit

operation is a useful feature.

The MUL AB instruction multiplies the Accumulator by the data in the B register and puts the

16-bit product into the concatenated B and Accumulator registers.

The DIV AB instruction divides the Accumulator by the data in the B register and leaves the

8-bit quotient in the Accumulator, and the 8-bit remainder in the B register.

In shift operations, dividing a number by 2n shifts its “n” bits to the right. Using DIV AB to

perform the division completes the shift in 4?s and leaves the B register holding the bits that

were shifted out. The DAA instruction is for BCD arithmetic operations. In BCD arithmetic,

ADD and ADDC instructions should always be followed by a DAA operation, to ensure that

the result is also in BCD.

DAA will not convert a binary number to BCD. The DAA operation produces a meaningful

result only as the second step in the addition of two BCD bytes.

Table 4. Arithmetic instructions

Mnemonic

Operation

ADD A,<byte>

ADDC A,<byte>

SUBB A,<byte>

INC

INC <byte>

INC DPTR

DEC

DEC <byte>

MUL AB

DIV AB

DA A

A = A + <byte>

A = A + <byte> + C

A = A – <byte> – C

A=A+1

<byte> = <byte> + 1

DPTR = DPTR + 1

A=A–1

<byte> = <byte> – 1

B:A = B x A

A = Int[ A / B ]

B = Mod[ A / B ]

Decimal Adjust

Addressing modes

Dir.

Ind.

Reg.

Imm.

X

X

X

X

X

X

X

X

X

X

X

X

Accumulator only

X

X

X

Data Pointer only

Accumulator only

X

X

X

Accumulator and B only

Accumulator and B only

Accumulator only

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