This is the abstract class for all machine MipsBranch instructions.

Delay Slot Instruction Mips Helmet
Delay Slot Instruction Mips Bike Helmet
Mips Branch Delay Slot Instruction
Delay Slot Instruction Mips Software

$Id: MipsBranch.java,v 1.15 2006-11-16 17:49:37 burrill Exp $

The problem gives two hints: it reminds us that branches and jumps are delayed and need their delay slots filled in and it hints at chaging the offset value in memory accesss instructions (lw,sw) when necessary. Pipelined MIPS While a typical instruction takes 3-5 cycles (i.e. 3-5 CPI), a pipelined processor targets 1 CPI. Instruction NOP (delay slot). Control MIPS uses more states for some instructions. Problem 1: 15 pts The MIPS implementation attached to this exam can execute a new instruction, xxx. Lines relevant to the instruction have XXXon the right hand side. (a) Describe instruction xxxas it might be described in an assembly language manual. Remember to describe. The instruction in the branch delay slot executes twice. It executes once because it’s in the branch delay slot. It executes again because it’s the destination of the branch. One final note is the case of emulated instructions.

Copyright 2005 by the Scale Compiler Group,
Department of Computer Science
University of Massachusetts,
Amherst MA. 01003, USA
All Rights Reserved.

Field Summary
`protected MipsInstruction`	`delaySlot` The delay slot instruction is kept as part of the branch.
`protected int`	`opcode` the instruction opcode

Constructor Summary
`protected`	`MipsBranch(int opcode, int numTargets, MipsInstruction delaySlot)`

Method Summary
`protected void`	`assembleDelay(Assembler asm, Emit emit)` Assemble the delay slot instruction.
`java.lang.String`	`assembleDisp(Assembler asm, Displacement disp)` Generate a String representation of a Displacement that can be used by the assembly code generater.
`boolean`	`canBeDeleted(RegisterSet registers)` Return true if the instruction can be deleted without changing program semantics.
`boolean`	`defs(int register, RegisterSet registers)` Return true if the instruction sets the register.
`protected void`	`delayToStringBuf(java.lang.StringBuffer buf)` toString() helper method.
`MipsInstruction`	`getDelaySlot()`
`int`	`getOpcode()` Return the numeric opcode of the instruction.
`int`	`instructionSize()` Return the number of bytes required for the Branch Instruction.
`boolean`	`isUnconditional()` Return true if the branch is an unconditional transfer of control to a new address.
`boolean`	`mods(int register, RegisterSet registers)` Return true if the instruction clobbers the register.
`void`	`remapDestRegister(int oldReg, int newReg)` Map the registers defined in the instruction as destinations to the specified register.
`void`	`remapRegisters(int[] map)` Map the virtual registers referenced in the instruction to the specified real registers.
`void`	`remapSrcRegister(int oldReg, int newReg)` Map the registers used in the instruction as sources to the specified register.
`protected void`	`setDelaySlot(MipsInstruction delaySlot)`
`protected void`	`setOpcode(int opcode)`
`void`	`specifyRegisterUsage(RegisterAllocator rs, int index, int strength)` Specify the registers used by this instruction.
`boolean`	`uses(int register, RegisterSet registers)` Return true if the instruction uses the register.

Methods inherited from class scale.backend.Branch
`additionalRegsKilled, additionalRegsSet, additionalRegsUsed, addTarget, copy, getBranchProbability, getExecutionCycles, getRegsKilled, getTarget, independent, isBranch, isCall, markAsCall, nullify, numTargets, setBranchProbability, toString, uses`

Methods inherited from class scale.backend.Instruction

assembler, clone, ehash, getBBID, getCopyDest, getCopySrc, getDestRegister, getFunctionalUnit, getLoopNumber, getNext, getPredicate, getPredicates, getSrcRegisters, getTag, isCopy, isLabel, isLoad, isMandatory, isMarker, isPhi, isPredicated, isPredicatedOnTrue, isPrefetch, isSpillInstruction, isSpillLoadPoint, isSpillStorePoint, isStore, markSpillInstruction, nullified, numPredicates, removePredicates, setBBID, setLoopNumber, setMandatory, setNext, setPredicate, setPredicate, setPredicatedOnTrue, setPredicates, setsSpecialReg, setTag, specifyNotSpillLoadPoint, specifySpillStorePoint

Methods inherited from class java.lang.Object
`equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

Field Detail

opcode

the instruction opcode

delaySlot

The delay slot instruction is kept as part of the branch.

Delay Slot Instruction Mips