Difference between revisions of "IOP16 Instructions Detail"
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=== BEZ - Branch if Equal to Zero === | === BEZ - Branch if Equal to Zero === | ||
| − | * If | + | * If Condition Code Zero-bit is set take branch |
=== BNZ - Branch if Not Zero === | === BNZ - Branch if Not Zero === | ||
| − | * If | + | * If Condition Code Zero-bit is not set take branch |
=== BEQ - Branch if Equal === | === BEQ - Branch if Equal === | ||
* Psuedo-Instruction (same as BEZ) | * Psuedo-Instruction (same as BEZ) | ||
| − | * If | + | * If Condition Code Zero-bit bit is set take branch |
=== BNE - Branch if Not Equal === | === BNE - Branch if Not Equal === | ||
* Psuedo-Instruction (Same as BNZ) | * Psuedo-Instruction (Same as BNZ) | ||
| − | * If | + | * If Condition Code Zero-bit bit is clear take branch |
== Misc Instructions == | == Misc Instructions == | ||
Revision as of 15:14, 17 April 2022
Contents
IOP16 Instructions
- Details of the instructions follow
- Some instructions are psuedo-ops which are replaced with equivalent instructions
- Used as convenience
Load Instruction
- Instruction to load register
LRI - Load Register with Immediate Value
- Load a register with an immediate value
Peripheral Load/Store Instructions
- Peripheral read/write instructions
IOR - I/O Read
- Read peripheral address into a register
IOW - I/O Write
- Write value from register to peripheral address
Shift/Rotate Instructions
- Shift/rotate instructions
- Logical/arithmetic operations
- The bottom 3-bits of the instruction have the count
- Count is set to 1
- Barrel shifter could be written to have other counts
- Shift/rotate instruction do not set the Condition Code Z-bit
SLL - Shift Logical Left
- Shift register left by 1
- Shifts in 0 to Least Significant bit
SLR - Shift Logical Right
- Shift register right by 1
- Shifts in 0 to Most Significant bit
SAL - Shift Arithmetic Left
- Shift register left by 1
- Shifts in 0 to Least Significant bit
SAR - Shift Arithmetic Right
- Shift register right by 1
- Shifts in 1 to Most Significant bit
RRL - Rotate Register Left
- Rotate Register left by 1
- Rotate Register MSB into Register Least Significant bit
RRR - Rotate Register Right
- Rotate register right by 1
- Rotate Register LSB into Register Most Significant bit
ALU Instruction
- Logical and Mathematical instructions
- Set Conditional Code Zero-bit
XRI - Exclusive-OR Register with Immediate Value
- Exclusive-OR Register with immediate value
- Store back into register
- Set Conditional Code Zero-bit
ORI - Logical OR Register with Immediate Value
- Logical OR Register with immediate value
- Store back into register
- Set Conditional Code Zero-bit
ARI - Logical AND Register with Immediate Value
- Logical AND Register with immediate value
- Store back into register
- Set Conditional Code Zero-bit
ADI - Add Register with Immediate Value
- Add Register with immediate value
- Store back into register
- Set Conditional Code Zero-bit
CMP - Compare Register with Immediate Value
- Compare register with Immediate value
- Set Conditional Code Zero-bit
Flow Control Instructions
- Various instructions that can alter program flow
- Some are conditional branches, Bxx
RTS - Return from Subroutine
- Pops the program stack to use as a return address
JSR - Jump to Subroutine
- Push next address onto stack
- Jump to address
JMP - Jump
- Jump to address
BEZ - Branch if Equal to Zero
- If Condition Code Zero-bit is set take branch
BNZ - Branch if Not Zero
- If Condition Code Zero-bit is not set take branch
BEQ - Branch if Equal
- Psuedo-Instruction (same as BEZ)
- If Condition Code Zero-bit bit is set take branch
BNE - Branch if Not Equal
- Psuedo-Instruction (Same as BNZ)
- If Condition Code Zero-bit bit is clear take branch
Misc Instructions
NOP - No operation
- Psuedo-Instruction
- Coded as ORI Reg8,0x00
HALT
- Psuedo-Instruction performs branch to self
Instruction Encoding
