Files
captain-amygdala.pistorm/a314/a314device/fix_mem_region.c
2021-05-17 14:45:46 +02:00

135 lines
2.9 KiB
C

/*
* Copyright 2020-2021 Niklas Ekström
*/
#include <exec/types.h>
#include <exec/execbase.h>
#include <exec/memory.h>
#include <proto/exec.h>
#include <proto/graphics.h>
#include "a314.h"
#include "fix_mem_region.h"
#include "protocol.h"
struct MemChunkList
{
struct MemChunk *first;
struct MemChunk *last;
ULONG free;
};
void add_chunk(struct MemChunkList *l, struct MemChunk *mc)
{
if (l->first == NULL)
l->first = mc;
else
l->last->mc_Next = mc;
l->last = mc;
l->free += mc->mc_Bytes;
}
struct MemHeader *split_region(struct MemHeader *lower, ULONG split_at)
{
struct MemHeader *upper = (struct MemHeader *)AllocMem(sizeof(struct MemHeader), MEMF_PUBLIC | MEMF_CLEAR);
struct MemChunkList ll = {NULL, NULL, 0};
struct MemChunkList ul = {NULL, NULL, 0};
struct MemChunk *mc = lower->mh_First;
while (mc != NULL)
{
struct MemChunk *next_chunk = mc->mc_Next;
mc->mc_Next = NULL;
ULONG start = (ULONG)mc;
ULONG end = start + mc->mc_Bytes;
if (end <= split_at)
add_chunk(&ll, mc);
else if (split_at <= start)
add_chunk(&ul, mc);
else
{
mc->mc_Bytes = split_at - start;
add_chunk(&ll, mc);
struct MemChunk *new_chunk = (struct MemChunk *)split_at;
new_chunk->mc_Next = NULL;
new_chunk->mc_Bytes = end - split_at;
add_chunk(&ul, new_chunk);
}
mc = next_chunk;
}
upper->mh_Node.ln_Type = NT_MEMORY;
upper->mh_Node.ln_Pri = lower->mh_Node.ln_Pri;
upper->mh_Node.ln_Name = lower->mh_Node.ln_Name; // Use a custom name?
upper->mh_Attributes = lower->mh_Attributes;
lower->mh_First = ll.first;
upper->mh_First = ul.first;
upper->mh_Lower = (APTR)split_at;
upper->mh_Upper = lower->mh_Upper;
lower->mh_Upper = (APTR)split_at;
lower->mh_Free = ll.free;
upper->mh_Free = ul.free;
return upper;
}
BOOL overlap(struct MemHeader *mh, ULONG lower, ULONG upper)
{
return lower < (ULONG)(mh->mh_Upper) && (ULONG)(mh->mh_Lower) < upper;
}
void mark_region_a314(ULONG address, ULONG size)
{
struct List *memlist = &(SysBase->MemList);
for (struct Node *node = memlist->lh_Head; node->ln_Succ != NULL; node = node->ln_Succ)
{
struct MemHeader *mh = (struct MemHeader *)node;
if (overlap(mh, address, address + size))
{
if ((ULONG)mh->mh_Lower < address)
{
mh->mh_Attributes &= ~MEMF_A314;
mh = split_region(mh, address);
}
else
Remove((struct Node *)mh);
if (address + size < (ULONG)mh->mh_Upper)
{
struct MemHeader *new_mh = split_region(mh, address + size);
new_mh->mh_Attributes &= ~MEMF_A314;
Enqueue(memlist, (struct Node *)new_mh);
}
mh->mh_Attributes |= MEMF_A314;
Enqueue(memlist, (struct Node *)mh);
return;
}
}
}
BOOL fix_memory()
{
Forbid();
mark_region_a314(ca->mem_base, ca->mem_size);
Permit();
return TRUE;
}
ULONG translate_address_a314(__reg("a0") void *address)
{
ULONG offset = (ULONG)address - ca->mem_base;
if (offset < ca->mem_size)
return offset;
return -1;
}