view mem.c @ 1637:95880d947257

Fix for VRAM byte write order broke VDP FIFO testing ROM results. This change cleans up VRAM writes and fixes the regression while preserving the correct VRAM byte write order
author Michael Pavone <pavone@retrodev.com>
date Sun, 11 Nov 2018 22:39:29 -0800
parents 101b5ce682fe
children 8e86cd581620
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/*
 Copyright 2013 Michael Pavone
 This file is part of BlastEm.
 BlastEm is free software distributed under the terms of the GNU General Public License version 3 or greater. See COPYING for full license text.
*/
#include <sys/mman.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>

#include "mem.h"
#include "arena.h"
#ifndef MAP_ANONYMOUS
#define MAP_ANONYMOUS MAP_ANON
#endif

#ifndef MAP_32BIT
#define MAP_32BIT 0
#endif

void * alloc_code(size_t *size)
{
	//start at the 1GB mark to allow plenty of room for sbrk based malloc implementations
	//while still keeping well within 32-bit displacement range for calling code compiled into the executable
	static uint8_t *next = (uint8_t *)0x40000000;
	uint8_t *ret = try_alloc_arena();
	if (ret) {
		return ret;
	}
	if (*size & (PAGE_SIZE -1)) {
		*size += PAGE_SIZE - (*size & (PAGE_SIZE - 1));
	}
	ret = mmap(next, *size, PROT_EXEC | PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_32BIT, -1, 0);
	if (ret == MAP_FAILED) {
		perror("alloc_code");
		return NULL;
	}
	track_block(ret);
	next = ret + *size;
	return ret;
}