static InstructionStream()
{
var instructions = new TInstruction[PageSize];
var operands = new int[PageSize];
for (var i = 0; i < PageSize; i++)
{
operands[i] = int.MinValue;
}
NullPage = new InstructionPage(instructions, operands, 0, PageSize)
{
ReferenceCount = int.MaxValue
};
}
private InstructionPage LoadPage(int pageIndex)
{
EnsurePagesCapacity(pageIndex + 1);
CleanHeadPage();
InstructionPage page = null;
if (pageIndex < PageCount)
{
page = Pages[pageIndex];
if (page.PageLength < PageSize)
{
LoadPosition();
page.PageLength += InstructionReader.ReadPage(page.PageLength, PageSize, page.InstructionsBuffer, page.OperandsBuffer);
SavePosition();
}
return(page);
}
if (Finished)
{
return(NullPage);
}
for (var iPage = PageCount - 1; iPage < pageIndex; iPage++)
{
page = ReadNextPage(PageCount);
Pages[page.PageIndex] = page;
PageCount++;
if (Finished)
{
break;
}
}
return(page);
}
private void AdvanceInstructionPosition(LexemeStream lexemeStream, int instructionPointer)
{
StartPosition = SeekableInstructionReader.Position;
StartInstructionPointer = instructionPointer;
var lexemeIndex = instructionPointer & LocalIndexMask;
var lexemePageIndex = instructionPointer >> PageIndexShift;
EnsurePagesCapacity(lexemePageIndex + 1);
for (var iPage = lexemeStream.HeadPage; iPage <= lexemePageIndex; iPage++)
{
InstructionReader.RentBuffers(PageSize, out var instructionsBuffer, out var operandsBuffer);
var pageSource = lexemeStream.Pages[iPage];
var pageCopy = new InstructionPage(instructionsBuffer, operandsBuffer, pageSource.PageIndex, pageSource.PageLength);
Array.Copy(pageSource.InstructionsBuffer, 0, pageCopy.InstructionsBuffer, 0, pageCopy.PageLength);
Array.Copy(pageSource.OperandsBuffer, 0, pageCopy.OperandsBuffer, 0, pageCopy.PageLength);
pageCopy.ReferenceCount = pageSource.ReferenceCount;
Pages[pageCopy.PageIndex] = pageCopy;
}
var lexemePage = Pages[lexemePageIndex];
lexemePage.PageLength = lexemeIndex;
for (var i = lexemeIndex; i < PageSize; i++)
{
lexemePage.OperandsBuffer[i] = int.MinValue;
lexemePage.InstructionsBuffer[i] = default;
}
HeadPage = lexemeStream.HeadPage;
PageCount = lexemePageIndex + 1;
ReadOperand(ref instructionPointer);
}
