#include <u.h>#include <libc.h>#include <thread.h>#include "cpu.h"#include "devs.h" enum {	DREAD = 0x10,	DWRITE = 0x11,}; typedef struct {	int op;	u32int memaddr;	u32int diskaddr;	u8int len;} diskop; Channel *dop;Channel *reply;int dfd;u32int disklen; voiddiskworker(void*){	u8int *buf;	long st;	diskop *op; 	buf = malloc(sizeof(u8int)*257);	threadsetname("nvp disk worker");	if(!buf)		panic("could not malloc disk buffer");	for(;;){		op = recvp(dop);		switch(op->op){		case DREAD:			if(op->memaddr >= memlen)				panic("disk: bad memory write");			st = pread(dfd, buf, op->len, op->diskaddr);			if(st != op->len)				panic("short read");			memcpy(&memory[op->memaddr], buf, op->len);			break;		case DWRITE:			if(op->memaddr >= memlen)				panic("disk: bad memory read");			memcpy(buf, &memory[op->memaddr], op->len);			st = pwrite(dfd, buf, op->len, op->diskaddr);			if(st != op->len)				panic("short write");			break;		default:			panic(smprint("unknown disk command %x", op->op));			break;		}		send(reply, &st);		free(op);	}} u8intdiskstatus(void){	long st; 	if(nbrecv(reply, &st) == 0)		return 0;	else		return 1;} voiddiskcmd(u8int oper){	diskop *op; 	op = malloc(sizeof(diskop));	if(op == nil)		panic("bad malloc");	op->diskaddr = disk.dat[0] << 24 | disk.dat[1] << 16 | disk.dat[2] << 8 | disk.dat[3];	op->memaddr = disk.dat[4] << 24 | disk.dat[5] << 16 | disk.dat[6] << 8 | disk.dat[7];	op->len = disk.dat[8];	op->op = oper;	sendp(dop, op);} voidinitdisk(int fd, u32int len){	disklen = len;	dfd = fd;	dop = chancreate(sizeof(uintptr), 5);	reply = chancreate(sizeof(long), 5);	proccreate(diskworker, nil, mainstacksize);	if(!dop || !reply)		panic("bad chancreate");} Device disk = {	.active = 1,	.init = nil,	.read = nil,	.write = nil,	.status = diskstatus,	.cmd = diskcmd,};