sizemem.c

来自「mips架构的bootloader,99左右的版本 但源代码现在没人更新了」· C语言 代码 · 共 85 行

/*************************************************************
 * File: lib/sizemem.c
 * Purpose: Part of C runtime library
 * Author: Phil Bunce ([e-mail])
 * Revision History:
 *	970304	Start of revision history
 *	970325	Replaced Ulong typedef with include of utypes.h
 */

#include <defines.h>
#include <mips.h>
#include <utypes.h>

#if 0 /* old version */
#define INCR 0x00010000		/* 64KB per SEG */
#define MARKER 0x55
#define MAXSEGS 512
#else /* new version */
#define BLOCKSIZE (16*1024)	/* 16KB per SEG */
#define MAXBLOCKS  4096
#define MARKER 0xfeedface
#endif

/*
 * Modified to support contiguous or non contiguous memory
 */

#ifdef TEST
main(argc,argv)
int argc;
char *argv[];
{
unsigned long addr,saved_sr;

printf("CLIENTPC=%08x FDATA=%08x\n",CLIENTPC,FDATA);
addr = CLIENTPC;
if (argc == 2) {
	sscanf(argv[1],"%x",&addr);
	}
	
saved_sr = mfc0(C0_SR);
mtc0(C0_SR,saved_sr&~SR_IEC);
printf("This board has %d Kbytes of available RAM at %08x\n",
	sizemem(addr)/1024,addr);
#ifdef LR4001
CFG4001 &= ~CFG_DBERR;
#endif
mtc0(C0_SR,saved_sr);
}
#endif

/*************************************************************
*  sizemem(adr)
*	measure the size of memory starting at 'adr'. The return
*	value is the number of bytes.
*	Note that if the adr specified is not at the start of the
*	block of memory, this function will wrap, and report the
*	total amount of memory, not just from adr to the end of memory.
*/
sizemem(adr)
Ulong *adr;
{
int i;
Ulong save0,save;
volatile Ulong *p,*block0;

block0 = (Ulong *)(((Ulong)adr)|K1BASE);
save0 = *block0;
*block0 = MARKER;
if (*block0 != MARKER) return(0);
*block0 = 0;
if (*block0 != 0) return(0);
for (i=1,p=block0;i<MAXBLOCKS;i++) {
        p += (BLOCKSIZE/4);
        save = *p;
        *p = MARKER;
        if (*block0 == MARKER) break;
        if (*p != MARKER) break;
        *p = save;
        }
*p = save;
*block0 = save0;
return(i*BLOCKSIZE);
}