| 1508 | | * Ensure that gcc does not use any register value before this instruction. This function is used |
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| 1509 | | * for assembler instructions with side-effects, e.g. port writes to magical guest ports causing |
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| 1510 | | * guest memory changes by the host |
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| 1511 | | * |
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| 1512 | | * @todo r=bird: There are two things I don't like there, 1) the name and 2) what about msc? |
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| 1513 | | * |
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| 1514 | | * Unless I'm not much mistaken this construct is what is 'barrier' or 'mb' in the linux |
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| 1515 | | * kernel. The ASMMem is used as prefix elsewhere in this file, so ASMMemory* is a confusing |
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| 1516 | | * way to name a new function. I think a more fitting name would be ASMCompilerBarrier, |
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| 1517 | | * ASMCompilerMemoryBarrier, or perhaps ASMMemBarrier. |
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| 1518 | | * |
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| 1519 | | * For MSC I guess _ReadWriteBarrier is what we're looking for. |
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| 1520 | | * See http://msdn2.microsoft.com/en-us/library/f20w0x5e(VS.80).aspx |
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| 1521 | | * |
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| 1522 | | * We should also add a little note about considering using 'volatile' similar to the one found |
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| 1523 | | * with the _ReadWriteBarrier docs. |
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| 1524 | | */ |
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| | 1509 | * Compiler memory barrier. |
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| | 1510 | * |
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| | 1511 | * Ensure that the compiler does not use any cached (register/tmp stack) memory |
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| | 1512 | * values or any outstanding writes when returning from this function. |
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| | 1513 | * |
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| | 1514 | * This function must be used if non-volatile data is modified by a |
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| | 1515 | * device or the VMM. Typical cases are port access, MMIO access, |
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| | 1516 | * trapping instruction, etc. |
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| | 1517 | */ |
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| | 1518 | DECLINLINE(void) ASMCompilerBarrier(void) |
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| | 1519 | { |
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