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/* ========================================================================
(C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Please see https://computerenhance.com for more information
======================================================================== */
static u32 GetHighestAddress(segmented_access SegMem)
{
u32 Result = SegMem.Mask;
return Result;
}
static u32 GetAbsoluteAddressOf(u32 Mask, u16 SegmentBase, u16 SegmentOffset, u16 AdditionalOffset)
{
u32 Result = (((u32)SegmentBase << 4) + (u32)(SegmentOffset + AdditionalOffset)) & Mask;
return Result;
}
static u32 GetAbsoluteAddressOf(segmented_access SegMem, u16 Offset)
{
u32 Result = GetAbsoluteAddressOf(SegMem.Mask, SegMem.SegmentBase, SegMem.SegmentOffset, Offset);
return Result;
}
static segmented_access MoveBaseBy(segmented_access Access, s32 Offset)
{
Access.SegmentOffset += Offset;
segmented_access Result = Access;
Result.SegmentBase += (Result.SegmentOffset >> 4);
Result.SegmentOffset &= 0xf;
assert(GetAbsoluteAddressOf(Result, 0) == GetAbsoluteAddressOf(Access, 0));
return Result;
}
static u8 *AccessMemory(segmented_access SegMem, u16 Offset)
{
u32 AbsAddr = GetAbsoluteAddressOf(SegMem, Offset);
u8 *Result = SegMem.Memory + AbsAddr;
return Result;
}
static b32 IsValid(segmented_access SegMem)
{
b32 Result = (SegMem.Mask != 0);
return Result;
}
static segmented_access FixedMemoryPow2(u32 SizePow2, u8 *Memory)
{
segmented_access Result = {};
Result.Memory = Memory;
Result.Mask = (1 << SizePow2) - 1;
return Result;
}
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