Motorola MC68HC05RC8 User Manual
Instruction Set
Instruction Types
MC68HC05RC16 — Rev. 3.0
General Release Specification
MOTOROLA
Instruction Set
89
10.3.8 Relative
Relative addressing is only for branch instructions. If the branch
condition is true, the CPU finds the effective branch destination by
adding the signed byte following the opcode to the contents of the
program counter. If the branch condition is not true, the CPU goes to the
next instruction. The offset is a signed, two’s complement byte that gives
a branching range of –128 to +127 bytes from the address of the next
location after the branch instruction.
condition is true, the CPU finds the effective branch destination by
adding the signed byte following the opcode to the contents of the
program counter. If the branch condition is not true, the CPU goes to the
next instruction. The offset is a signed, two’s complement byte that gives
a branching range of –128 to +127 bytes from the address of the next
location after the branch instruction.
When using the Motorola assembler, the programmer does not need to
calculate the offset, because the assembler determines the proper offset
and verifies that it is within the span of the branch.
calculate the offset, because the assembler determines the proper offset
and verifies that it is within the span of the branch.
10.4 Instruction Types
The MCU instructions fall into the following five categories:
•
Register/Memory Instructions
•
Read-Modify-Write Instructions
•
Jump/Branch Instructions
•
Bit Manipulation Instructions
•
Control Instructions