SAB80515 Datasheet, PDF (127/270 Pages) Siemens Semiconductor Group – 8-Bit Single-Chip Microcontroller Family

Instruction Set
9
Instruction Set
The SAB 80(C)515/80(C)535 instruction set includes 111 instructions, 49 of which are single-byte,
45 two-byte and 17 three-byte instructions. The instruction opcode format consists of a function
mnemonic followed by a ”destination, source” operand field. This field specifies the data type and
addressing method(s) to be used.
Like all other members of the 8051-family, the SAB 80(C)515/80(C)535 can be programmed with
the same instruction set common to the basic member, the SAB 8051.
Thus, the SAB 80(C)515/80(C)535 is 100% software compatible to the SAB 8051 and may be
programmed with 8051 assembler or high-level languages.
9.1 Addressing Modes
The SAB 80(C)515/80(C)535 uses five addressing modes:
– register
– direct
– immediate
– register indirect
– base register plus index-register indirect
Table 9-1 summarizes the memory spaces which may be accessed by each of the addressing
modes.
Register Addressing
Register addressing accesses the eight working registers (R0 - R7) of the selected register bank.
The least significant bit of the instruction opcode indicates which register is to be used. ACC, B,
DPTR and CY, the Boolean processor accumulator, can also be addressed as registers.
Direct Addressing
Direct addressing is the only method of accessing the special function registers. The lower
128 bytes of internal RAM are also directly addressable.
Immediate Addressing
Immediate addressing allows constants to be part of the instruction in program memory.
Semiconductor Group
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