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Allow unaligned load/store in QVM interpreter/x86 compiler

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constructions like (dataMask & ~3) was used to protect against out-of-bound load/store when address is 4-byte closer to dataMask
 but at the same time it effectively cut low address bits for ALL load/store operations which is totally wrong in terms of conformance to ALLOWED (i.e. generated by q3lcc from C sources) low-level operations like packed binary data parsing
This commit is contained in:
ec- 2017-03-15 11:42:58 +02:00 • committed by Tim Angus
parent abce15055c
commit 566fb0edfc
4 changed files with 17 additions and 14 deletions
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14
code/qcommon/vm_interpreted.c
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@ -436,31 +436,31 @@ nextInstruction2:
return 0;
}
#endif
r0 = opStack[opStackOfs] = *(int *) &image[r0 & dataMask & ~3 ];
r0 = opStack[opStackOfs] = *(int *) &image[ r0 & dataMask ];
goto nextInstruction2;
case OP_LOAD2:
r0 = opStack[opStackOfs] = *(unsigned short *)&image[ r0&dataMask&~1 ];
r0 = opStack[opStackOfs] = *(unsigned short *)&image[ r0 & dataMask ];
goto nextInstruction2;
case OP_LOAD1:
r0 = opStack[opStackOfs] = image[ r0&dataMask ];
r0 = opStack[opStackOfs] = image[ r0 & dataMask ];
goto nextInstruction2;
case OP_STORE4:
*(int *)&image[ r1&(dataMask & ~3) ] = r0;
*(int *)&image[ r1 & dataMask ] = r0;
opStackOfs -= 2;
goto nextInstruction;
case OP_STORE2:
*(short *)&image[ r1&(dataMask & ~1) ] = r0;
*(short *)&image[ r1 & dataMask ] = r0;
opStackOfs -= 2;
goto nextInstruction;
case OP_STORE1:
image[ r1&dataMask ] = r0;
image[ r1 & dataMask ] = r0;
opStackOfs -= 2;
goto nextInstruction;
case OP_ARG:
// single byte offset from programStack
*(int *)&image[ (codeImage[programCounter] + programStack)&dataMask&~3 ] = r0;
*(int *)&image[ (codeImage[programCounter] + programStack) & dataMask ] = r0;
opStackOfs--;
programCounter += 1;
goto nextInstruction;