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Program Counter Relative Addressing: Difference between revisions
From SnesLab
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'''Program Counter Relative Addressing''' is supported by nine instructions: | '''Program Counter Relative Addressing''' is supported by nine instructions on the [[65c816]]: | ||
* [[BCC]] (opcode 90) | * [[BCC]] (opcode 90) | ||
Revision as of 19:41, 4 August 2024
Program Counter Relative Addressing is supported by nine instructions on the 65c816:
- BCC (opcode 90)
- BCS (opcode B0)
- BEQ (opcode F0)
- BMI (opcode 30)
- BNE (opcode D0)
- BPL (opcode 10)
- BRA (opcode 80)
- BVC (opcode 50)
- BVS (opcode 70)
All of which are two bytes long.
The effective address is generated by sign-extending the 8-bit operand to 16 bits and then adding it to the program counter. The program bank register remains the same.
Syntax
BRA label
See Also
Reference
- Eyes & Lichty page 399, https://archive.org/details/0893037893ProgrammingThe65816/page/399
- section 3.5.21 of 65c816 datasheet, https://westerndesigncenter.com/wdc/documentation/w65c816s.pdf
- Clark, Bruce. http://www.6502.org/tutorials/65c816opcodes.html#5.18