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// Fake IDE disk; stores blocks in memory.
// Useful for running kernel without scratch disk.
#include "types.h"
#include "defs.h"
#include "param.h"
#include "mmu.h"
#include "proc.h"
#include "x86.h"
#include "traps.h"
#include "spinlock.h"
#include "fs.h"
#include "buf.h"
extern uchar _binary_fs_img_start[], _binary_fs_img_size[];
static int disksize;
static uchar *memdisk;
void
ideinit(void)
{
memdisk = _binary_fs_img_start;
disksize = (uint)_binary_fs_img_size/BSIZE;
}
// Interrupt handler.
void
ideintr(void)
{
// no-op
}
// Sync buf with disk.
// If B_DIRTY is set, write buf to disk, clear B_DIRTY, set B_VALID.
// Else if B_VALID is not set, read buf from disk, set B_VALID.
void
iderw(struct buf *b)
{
uchar *p;
if(!(b->flags & B_BUSY))
panic("iderw: buf not busy");
if((b->flags & (B_VALID|B_DIRTY)) == B_VALID)
panic("iderw: nothing to do");
if(b->dev != 1)
panic("iderw: request not for disk 1");
if(b->blockno >= disksize)
panic("iderw: block out of range");
p = memdisk + b->blockno*BSIZE;
if(b->flags & B_DIRTY){
b->flags &= ~B_DIRTY;
memmove(p, b->data, BSIZE);
} else
memmove(b->data, p, BSIZE);
b->flags |= B_VALID;
}
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