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| − | <!-- Tutorial:CodeInjection_Floats --> | + | <span style="font-size:25px;color:red">Sorry! Content not available.</span> |
| − | [[Category:Tutorial]]
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| − | [[Category:Auto Assembler]]
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| − | {{DISPLAYTITLE:Code Injection - Working with Floats}}
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| − | This tutorial builds on the topic of Code Injection:
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| − | {{TutorialsCodeInjection}}
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| − | | |
| − | <br>
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| − | Let's say you have a float and some code that increases the value.
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| − | <pre>
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| − | addss [eax+10],xmm0
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| − | </pre>
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| − | :Note: '''SS''' is for singles and '''SD''' is for doubles.
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| − | <blockquote>
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| − | What if what writes to the value is only a [[Assembler:Commands:MOVSS|MOVSS]]. Try to find a spot above the write instruction that has an [[Assembler:Commands:ADDSS|ADDSS]] (or a [[Assembler:Commands:SUBSS|SUBSS]] depending on what you want to do).
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| − | <pre>
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| − | addss xmm0,xmm1
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| − | //...
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| − | movss [eax+10],xmm0
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| − | </pre>
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| − | </blockquote>
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| − | | |
| − | <br>
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| − | == Editable value ==
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| − | We could use a [[Auto Assembler:label|label]], giving it some memory. And optionally [[Auto_Assembler:registerSymbol|register]] it so the label can be used on the table as an address.
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| − | <pre>
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| − | //...
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| − | alloc(someMem, 0x400)
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| − | //...
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| − | label(someSymbol)
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| − | registerSymbol(someSymbol)
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| − | //...
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| − | someMem:
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| − | //...
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| − | movss xmm0,[someSymbol]
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| − | addss [eax+10],xmm0
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| − | //...
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| − | jmp return
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| − | //...
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| − | someSymbol:
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| − | dd (float)100
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| − | //...
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| − | </pre>
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| − | | |
| − | <br>
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| − | == Adding a Multiplier ==
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| − | We could add an editable value like above but use [[Assembler:Commands:MULSS|MULSS]] to add a multiplier to the script.
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| − | <pre>
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| − | //...
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| − | alloc(someMem, 0x400)
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| − | //...
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| − | label(someSymbol)
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| − | registerSymbol(someSymbol)
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| − | //...
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| − | someMem:
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| − | //...
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| − | mulss xmm0,[someSymbol]
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| − | addss [eax+10],xmm0
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| − | //...
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| − | jmp return
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| − | //...
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| − | someSymbol:
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| − | dd (float)100
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| − | //...
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| − | </pre>
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| − | | |
| − | <br>
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| − | == Calculate a value for a Multiplier ==
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| − | Let's say we just can't find an [[Assembler:Commands:ADDSS|ADDSS]] or a [[Assembler:Commands:SUBSS|SUBSS]], and all we have is a [[Assembler:Commands:MOVSS|MOVSS]].
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| − | <pre>
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| − | movss [eax+10],xmm0
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| − | </pre>
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| − | | |
| − | We can just do some math in the script, to calculate a value for a multiplier.
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| − | <pre>
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| − | //...
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| − | alloc(someMem, 0x400)
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| − | //...
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| − | label(someSymbol)
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| − | registerSymbol(someSymbol)
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| − | //...
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| − | someMem:
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| − | //...
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| − | subss xmm0,[eax+10]
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| − | mulss xmm0,[someSymbol]
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| − | addss xmm0,[eax+10]
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| − | movss [eax+10],xmm0
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| − | //...
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| − | jmp return
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| − | //...
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| − | someSymbol:
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| − | dd (float)10
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| − | //...
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| − | </pre>
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| − | | |
| − | <br>
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| − | == Working with doubles ==
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| − | Let's say the game use doubles, we can use [[Assembler:Commands:ADDSD|ADDSD]], [[Assembler:Commands:SUBSD|SUBSD]], [[Assembler:Commands:MULSD|MULSD]], and [[Assembler:Commands:MOVSD|MOVSD]] instead. We just need to also make our scripts value a double.
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| − | <pre>
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| − | movsd [eax+10],xmm0
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| − | </pre>
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| − | | |
| − | So to calculate a value for a multiplier.
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| − | <pre>
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| − | //...
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| − | alloc(someMem, 0x400)
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| − | //...
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| − | label(someSymbol)
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| − | registerSymbol(someSymbol)
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| − | //...
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| − | someMem:
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| − | //...
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| − | subsd xmm0,[eax+10]
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| − | mulsd xmm0,[someSymbol]
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| − | addsd xmm0,[eax+10]
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| − | movsd [eax+10],xmm0
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| − | //...
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| − | jmp return
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| − | //...
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| − | someSymbol:
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| − | dq (double)10
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| − | //...
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| − | </pre>
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| − | | |
| − | <br>
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| − | == Working with packed instructions ==
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| − | Some times (especially with vectors) you'll see packed instructions, like [[Assembler:Commands:MOVAPS|MOVAPS]], [[Assembler:Commands:MOVUPS|MOVUPS]], [[Assembler:Commands:ADDPS|ADDPS]], [[Assembler:Commands:SUBPS|SUBPS]], [[Assembler:Commands:MULPS|MULPS]]. These type of instructions work on 16 bytes at a time.
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| − | | |
| − | So let's say you have some code accessing the player coordinate deltas, and it's using packed instructions.
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| − | <pre>
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| − | addps [eax+10],xmm0
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| − | </pre>
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| − | | |
| − | So let's add a multiplier for this.
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| − | <pre>
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| − | //...
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| − | alloc(someMem, 0x400)
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| − | //...
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| − | label(someSymbol)
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| − | registerSymbol(someSymbol)
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| − | //...
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| − | someMem:
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| − | //...
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| − | mulps xmm0,[someSymbol]
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| − | addps [eax+10],xmm0
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| − | //...
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| − | jmp return
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| − | //...
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| − | someSymbol:
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| − | dd (float)1.75
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| − | dd (float)1.75
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| − | dd (float)1.25
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| − | dd (float)1
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| − | //...
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| − | </pre> | |
| − | | |
| − | <br>
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| − | == Calculate a value for packed instruction ==
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| − | Let's say we just can't find an [[Assembler:Commands:ADDPS|ADDPS]] or a [[Assembler:Commands:SUBPS|SUBPS]], and all we have is a [[Assembler:Commands:MOVUPS|MOVUPS]] or a [[Assembler:Commands:MOVAPS|MOVAPS]].
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| − | <pre>
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| − | movups [eax+10],xmm0
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| − | </pre>
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| − | | |
| − | We can just do some math in the script, to calculate a value for a multiplier.
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| − | <pre>
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| − | //...
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| − | alloc(someMem, 0x400)
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| − | //...
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| − | label(someSymbol)
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| − | registerSymbol(someSymbol)
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| − | //...
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| − | someMem:
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| − | //...
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| − | subps xmm0,[eax+10]
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| − | mulps xmm0,[someSymbol]
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| − | addps xmm0,[eax+10]
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| − | movups [eax+10],xmm0
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| − | //...
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| − | jmp return
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| − | //...
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| − | someSymbol:
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| − | dd (float)1.75
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| − | dd (float)1.75
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| − | dd (float)1.25
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| − | dd (float)1
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| − | //...
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| − | </pre>
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| − | | |
| − | We could use the [[Auto_Assembler:align|align]] command and then be able to use aligned instructions. So if the injection point looks like this.
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| − | <pre>
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| − | movups [eax+10],xmm0
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| − | </pre>
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| − | | |
| − | Then we could make a script like this.
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| − | <pre>
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| − | //...
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| − | alloc(someMem, 0x400)
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| − | //...
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| − | label(someSymbol)
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| − | registerSymbol(someSymbol)
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| − | //...
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| − | someMem:
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| − | //...
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| − | subps xmm0,[eax+10]
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| − | mulps xmm0,[someSymbol]
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| − | addps xmm0,[eax+10]
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| − | movaps [eax+10],xmm0
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| − | //...
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| − | jmp return
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| − | //...
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| − | align 10 CC
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| − | someSymbol:
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| − | dd (float)1.75
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| − | dd (float)1.75
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| − | dd (float)1.25
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| − | dd (float)1
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| − | //...
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| − | </pre>
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| − | | |
| − | <br>
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| − | == Working with the FPU registry ==
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| − | Some times you'll find some opcode that uses the [https://en.wikibooks.org/wiki/X86_Assembly/Floating_Point FPU] registry. These include [[Assembler:Commands:FLD|FLD]], [[Assembler:Commands:FMUL|FMUL]], [[Assembler:Commands:FADD|FADD]], [[Assembler:Commands:FSUB|FSUB]], [[Assembler:Commands:FST|FST]], [[Assembler:Commands:FSTP|FSTP]].
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| − | | |
| − | So with singles it might look like this.
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| − | <pre>
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| − | fld dword ptr [ebp+20]
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| − | fmul dword ptr [ebp+40]
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| − | fadd dword ptr [eax+10]
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| − | fstp dword ptr [eax+10]
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| − | </pre>
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| − | | |
| − | And if it was with doubles it might look like this.
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| − | <pre>
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| − | fld qword ptr [ebp+20]
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| − | fmul qword ptr [ebp+40]
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| − | fadd qword ptr [eax+10]
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| − | fstp qword ptr [eax+10]
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| − | </pre>
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| − | | |
| − | So say we have some opcode that decreases health that looks like this.
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| − | <pre>
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| − | fld dword ptr [eax+10]
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| − | fsub dword ptr [ebp+20]
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| − | fstp dword ptr [eax+10]
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| − | </pre>
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| − | | |
| − | So the add a multiplier to this we could make a script like this.
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| − | <pre>
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| − | //...
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| − | alloc(someMem, 0x400)
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| − | //...
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| − | label(someSymbol)
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| − | registerSymbol(someSymbol)
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| − | //...
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| − | someMem:
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| − | //...
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| − | fld dword ptr [ebp+20]
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| − | fmul dword ptr [someSymbol]
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| − | fld dword ptr [eax+10]
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| − | fsub st(0),st(1)
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| − | fstp dword ptr [eax+10]
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| − | fstp st(0)
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| − | //...
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| − | jmp return
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| − | //...
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| − | someSymbol:
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| − | dd (float)0.25
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| − | //...
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| − | </pre>
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| − | | |
| − | <br>
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| − | | |
| − | == See Also ==
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| − | {{TutorialsAA}}
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