ref: b548687a8ed1d0a159c9d3f3f921d93bbb56908e
dir: /appl/cmd/disk/ftl.b/
#
# basic Flash Translation Layer driver
# see for instance the Intel technical paper
# ``Understanding the Flash Translation Layer (FTL) Specification''
# Order number 297816-001 (online at www.intel.com)
#
# a public driver by David Hinds, [email protected]
# further helps with some details.
#
# this driver uses the common simplification of never storing
# the VBM on the medium (a waste of precious flash!) but
# rather building it on the fly as the block maps are read.
#
# Plan 9 driver (c) 1997 by C H Forsyth ([email protected])
# This driver may be used or adapted by anyone for any non-commercial purpose.
#
# adapted for Inferno 1998 by C H Forsyth, Vita Nuova Limited, York, England ([email protected])
#
# C H Forsyth and Vita Nuova Limited expressly allow Lucent Technologies
# to use this driver freely for any Inferno-related purposes whatever,
# including commercial applications.
#
# TO DO:
# check error handling details for get/put flash
# bad block handling
# reserved space in formatted size
# possibly block size as parameter
# fetch parameters from header on init
#
# Adapted to a ftl formatter for Inferno 2000 by J R Firth, Vita Nuova Limited
# usage : ftl flashsize secsize inputfile outputfile
# outputfile will then be a ftl image of inputfile
# nb assumes the base address is zero
#
# Converted to limbo for Inferno 2000 by JR Firth, Vita Nuova Holdings Limited
#
implement Ftlimage;
include "sys.m";
include "draw.m";
sys : Sys;
OREAD, OWRITE, FD, open, create, read, write, print, fprint : import sys;
Ftlimage : module
{
init : fn(nil : ref Draw->Context, argv : list of string);
};
stderr : ref FD;
flashsize, secsize : int;
flashm : array of byte;
trace : int = 0;
Eshift : con 18; # 2^18=256k; log2(eraseunit)
Flashseg : con 1<<Eshift;
Bshift : con 9; # 2^9=512
Bsize : con 1<<Bshift;
BAMoffset : con 16r100;
Nolimit : con ~0;
USABLEPCT : con 95; # release only this % to client
FTLDEBUG : con 0;
# erase unit header (defined by FTL specification)
# offsets into Merase
O_LINKTUPLE : con 0;
O_ORGTUPLE : con 5;
O_NXFER : con 15;
O_NERASE : con 16;
O_ID : con 20;
O_BSHIFT : con 22;
O_ESHIFT : con 23;
O_PSTART : con 24;
O_NUNITS : con 26;
O_PSIZE : con 28;
O_VBMBASE : con 32;
O_NVBM : con 36;
O_FLAGS : con 38;
O_CODE : con 39;
O_SERIAL : con 40;
O_ALTOFFSET : con 44;
O_BAMOFFSET : con 48;
O_RSV2 : con 52;
ERASEHDRLEN : con 64;
# special unit IDs
XferID : con 16rffff;
XferBusy : con 16r7fff;
# special BAM addresses
Bfree : con -1; #16rffffffff
Bwriting : con -2; #16rfffffffe
Bdeleted : con 0;
# block types
TypeShift : con 7;
BlockType : con (1<<TypeShift)-1;
ControlBlock : con 16r30;
DataBlock : con 16r40;
ReplacePage : con 16r60;
BadBlock : con 16r70;
BNO(va : int) : int
{
return va>>Bshift;
}
MKBAM(b : int,t : int) : int
{
return (b<<Bshift)|t;
}
Terase : adt {
x : int;
id : int;
offset : int;
bamoffset : int;
nbam : int;
bam : array of byte;
bamx : int;
nfree : int;
nused : int;
ndead : int;
nbad : int;
nerase : int;
};
Ftl : adt {
base : int; # base of flash region
size : int; # size of flash region
segsize : int; # size of flash segment (erase unit)
eshift : int; # log2(erase-unit-size)
bshift : int; # log2(bsize)
bsize : int;
nunit : int; # number of segments (erase units)
unit : array of ref Terase;
lastx : int; # index in unit of last allocation
xfer : int; # index in unit of current transfer unit (-1 if none)
nfree : int; # total free space in blocks
nblock : int; # total space in blocks
rwlimit : int; # user-visible block limit (`formatted size')
vbm : array of int; # virtual block map
fstart : int; # address of first block of data in a segment
trace : int; # (debugging) trace of read/write actions
detach : int; # free Ftl on last close
# scavenging variables
needspace : int;
hasproc : int;
};
# Ftl.detach
Detached : con 1; # detach on close
Deferred : con 2; # scavenger must free it
ftls : ref Ftl;
ftlstat(sz : int)
{
print("16r%x:16r%x:16r%x\n", ftls.rwlimit*Bsize, sz, flashsize);
print("%d:%d:%d in 512b blocks\n", ftls.rwlimit, sz>>Bshift, flashsize>>Bshift);
}
ftlread(buf : array of byte, n : int, offset : int) : int
{
ftl : ref Ftl;
e : ref Terase;
nb : int;
a : int;
pb : int;
mapb : int;
if(n <= 0 || n%Bsize || offset%Bsize) {
fprint(stderr, "ftl: bad read\n");
exit;
}
ftl = ftls;
nb = n/Bsize;
offset /= Bsize;
if(offset >= ftl.rwlimit)
return 0;
if(offset+nb > ftl.rwlimit)
nb = ftl.rwlimit - offset;
a = 0;
for(n = 0; n < nb; n++){
(mapb, e, pb) = mapblk(ftl, offset+n);
if(mapb)
getflash(ftl, buf[a:], e.offset + pb*Bsize, Bsize);
else
memset(buf[a:], 0, Bsize);
a += Bsize;
}
return a;
}
ftlwrite(buf : array of byte, n : int, offset : int) : int
{
ns, nb : int;
a : int;
e, oe : ref Terase;
ob, v : int;
ftl : ref Ftl;
mapb : int;
if(n <= 0)
return 0;
ftl = ftls;
if(n <= 0 || n%Bsize || offset%Bsize) {
fprint(stderr, "ftl: bad write\n");
exit;
}
nb = n/Bsize;
offset /= Bsize;
if(offset >= ftl.rwlimit)
return 0;
if(offset+nb > ftl.rwlimit)
nb = ftl.rwlimit - offset;
a = 0;
for(n = 0; n < nb; n++){
ns = 0;
while((v = allocblk(ftl)) == 0)
if(!scavenge(ftl) || ++ns > 3){
fprint(stderr, "ftl: flash memory full\n");
}
(mapb, oe, ob) = mapblk(ftl, offset+n);
if(!mapb)
oe = nil;
e = ftl.unit[v>>16];
v &= 16rffff;
putflash(ftl, e.offset + v*Bsize, buf[a:], Bsize);
putbam(ftl, e, v, MKBAM(offset+n, DataBlock));
# both old and new block references exist in this window (can't be closed?)
ftl.vbm[offset+n] = (e.x<<16) | v;
if(oe != nil){
putbam(ftl, oe, ob, Bdeleted);
oe.ndead++;
}
a += Bsize;
}
return a;
}
mkftl(fname : string, base : int, size : int, eshift : int, op : string) : ref Ftl
{
i, j, nov, segblocks : int;
limit : int;
e : ref Terase;
ftl := ref Ftl;
ftl.lastx = 0;
ftl.detach = 0;
ftl.needspace = 0;
ftl.hasproc = 0;
ftl.trace = 0;
limit = flashsize;
if(size == Nolimit)
size = limit-base;
if(base >= limit || size > limit || base+size > limit || eshift < 8 || (1<<eshift) > size) {
fprint(stderr, "bad flash space parameters");
exit;
}
if(FTLDEBUG || ftl.trace || trace)
print("%s flash %s #%x:#%x limit #%x\n", op, fname, base, size, limit);
ftl.base = base;
ftl.size = size;
ftl.bshift = Bshift;
ftl.bsize = Bsize;
ftl.eshift = eshift;
ftl.segsize = 1<<eshift;
ftl.nunit = size>>eshift;
nov = ((ftl.segsize/Bsize)*4 + BAMoffset + Bsize - 1)/Bsize; # number of overhead blocks per segment (header, and BAM itself)
ftl.fstart = nov;
segblocks = ftl.segsize/Bsize - nov;
ftl.nblock = ftl.nunit*segblocks;
if(ftl.nblock >= 16r10000)
ftl.nblock = 16r10000;
ftl.vbm = array[ftl.nblock] of int;
ftl.unit = array[ftl.nunit] of ref Terase;
if(ftl.vbm == nil || ftl.unit == nil) {
fprint(stderr, "out of mem");
exit;
}
for(i=0; i<ftl.nblock; i++)
ftl.vbm[i] = 0;
if(op == "format"){
for(i=0; i<ftl.nunit-1; i++)
eraseinit(ftl, i*ftl.segsize, i, 1);
eraseinit(ftl, i*ftl.segsize, XferID, 1);
}
ftl.xfer = -1;
for(i=0; i<ftl.nunit; i++){
e = eraseload(ftl, i, i*ftl.segsize);
if(e == nil){
fprint(stderr, "ftl: logical segment %d: bad format\n", i);
continue;
}
if(e.id == XferBusy){
e.nerase++;
eraseinit(ftl, e.offset, XferID, e.nerase);
e.id = XferID;
}
for(j=0; j<ftl.nunit; j++)
if(ftl.unit[j] != nil && ftl.unit[j].id == e.id){
fprint(stderr, "ftl: duplicate erase unit #%x\n", e.id);
erasefree(e);
e = nil;
break;
}
if(e != nil){
ftl.unit[e.x] = e;
if(e.id == XferID)
ftl.xfer = e.x;
if (FTLDEBUG || ftl.trace || trace)
fprint(stderr, "ftl: unit %d:#%x used %d free %d dead %d bad %d nerase %d\n",
e.x, e.id, e.nused, e.nfree, e.ndead, e.nbad, e.nerase);
}
}
if(ftl.xfer < 0 && ftl.nunit <= 0 || ftl.xfer >= 0 && ftl.nunit <= 1) {
fprint(stderr, "ftl: no valid flash data units");
exit;
}
if(ftl.xfer < 0)
fprint(stderr, "ftl: no transfer unit: device is WORM\n");
else
ftl.nblock -= segblocks; # discount transfer segment
if(ftl.nblock >= 1000)
ftl.rwlimit = ftl.nblock-100; # TO DO: variable reserve
else
ftl.rwlimit = ftl.nblock*USABLEPCT/100;
return ftl;
}
ftlfree(ftl : ref Ftl)
{
if(ftl != nil){
ftl.unit = nil;
ftl.vbm = nil;
ftl = nil;
}
}
#
# this simple greedy algorithm weighted by nerase does seem to lead
# to even wear of erase units (cf. the eNVy file system)
#
bestcopy(ftl : ref Ftl) : ref Terase
{
e, be : ref Terase;
i : int;
be = nil;
for(i=0; i<ftl.nunit; i++)
if((e = ftl.unit[i]) != nil && e.id != XferID && e.id != XferBusy && e.ndead+e.nbad &&
(be == nil || e.nerase <= be.nerase && e.ndead >= be.ndead))
be = e;
return be;
}
copyunit(ftl : ref Ftl, from : ref Terase, too : ref Terase) : int
{
i, nb : int;
id := array[2] of byte;
bam : array of byte;
buf : array of byte;
v, bno : int;
if(FTLDEBUG || ftl.trace || trace)
print("ftl: copying %d (#%x) to #%x\n", from.id, from.offset, too.offset);
too.nbam = 0;
too.bam = nil;
bam = nil;
buf = array[Bsize] of byte;
if(buf == nil)
return 0;
PUT2(id, XferBusy);
putflash(ftl, too.offset+O_ID, id, 2);
# make new BAM
nb = from.nbam*4;
bam = array[nb] of byte;
memmove(bam, from.bam, nb);
too.nused = 0;
too.nbad = 0;
too.nfree = 0;
too.ndead = 0;
for(i = 0; i < from.nbam; i++)
bv := GET4(bam[4*i:]);
case(bv){
Bwriting or
Bdeleted or
Bfree =>
PUT4(bam[4*i:], Bfree);
too.nfree++;
break;
* =>
case(bv&BlockType){
DataBlock or
ReplacePage =>
v = bv;
bno = BNO(v & ~BlockType);
if(i < ftl.fstart || bno >= ftl.nblock){
print("ftl: unit %d:#%x bad bam[%d]=#%x\n", from.x, from.id, i, v);
too.nfree++;
PUT4(bam[4*i:], Bfree);
break;
}
getflash(ftl, buf, from.offset+i*Bsize, Bsize);
putflash(ftl, too.offset+i*Bsize, buf, Bsize);
too.nused++;
break;
ControlBlock =>
too.nused++;
break;
* =>
# case BadBlock: # it isn't necessarily bad in this unit
too.nfree++;
PUT4(bam[4*i:], Bfree);
break;
}
}
# for(i=0; i<from.nbam; i++){
# v = GET4(bam[4*i:]);
# if(v != Bfree && ftl.trace > 1)
# print("to[%d]=#%x\n", i, v);
# PUT4(bam[4*i:], v);
# }
putflash(ftl, too.bamoffset, bam, nb); # BUG: PUT4 ? IS IT ?
# for(i=0; i<from.nbam; i++){
# v = GET4(bam[4*i:]);
# PUT4(bam[4*i:], v);
# }
too.id = from.id;
PUT2(id, too.id);
putflash(ftl, too.offset+O_ID, id, 2);
too.nbam = from.nbam;
too.bam = bam;
ftl.nfree += too.nfree - from.nfree;
buf = nil;
return 1;
}
mustscavenge(a : ref Ftl) : int
{
return a.needspace || a.detach == Deferred;
}
donescavenge(a : ref Ftl) : int
{
return a.needspace == 0;
}
scavengeproc(arg : ref Ftl)
{
ftl : ref Ftl;
i : int;
e, ne : ref Terase;
ftl = arg;
if(mustscavenge(ftl)){
if(ftl.detach == Deferred){
ftlfree(ftl);
fprint(stderr, "scavenge out of memory\n");
exit;
}
if(FTLDEBUG || ftl.trace || trace)
print("ftl: scavenge %d\n", ftl.nfree);
e = bestcopy(ftl);
if(e == nil || ftl.xfer < 0 || (ne = ftl.unit[ftl.xfer]) == nil || ne.id != XferID || e == ne)
;
else if(copyunit(ftl, e, ne)){
i = ne.x; ne.x = e.x; e.x = i;
ftl.unit[ne.x] = ne;
ftl.unit[e.x] = e;
ftl.xfer = e.x;
e.id = XferID;
e.nbam = 0;
e.bam = nil;
e.bamx = 0;
e.nerase++;
eraseinit(ftl, e.offset, XferID, e.nerase);
}
if(FTLDEBUG || ftl.trace || trace)
print("ftl: end scavenge %d\n", ftl.nfree);
ftl.needspace = 0;
}
}
scavenge(ftl : ref Ftl) : int
{
if(ftl.xfer < 0 || bestcopy(ftl) == nil)
return 0; # you worm!
if(!ftl.hasproc){
ftl.hasproc = 1;
}
ftl.needspace = 1;
scavengeproc(ftls);
return ftl.nfree;
}
putbam(ftl : ref Ftl, e : ref Terase, n : int, entry : int)
{
b := array[4] of byte;
PUT4(e.bam[4*n:], entry);
PUT4(b, entry);
putflash(ftl, e.bamoffset + n*4, b, 4);
}
allocblk(ftl : ref Ftl) : int
{
e : ref Terase;
i, j : int;
i = ftl.lastx;
do{
e = ftl.unit[i];
if(e != nil && e.id != XferID && e.nfree){
ftl.lastx = i;
for(j=e.bamx; j<e.nbam; j++)
if(GET4(e.bam[4*j:])== Bfree){
putbam(ftl, e, j, Bwriting);
ftl.nfree--;
e.nfree--;
e.bamx = j+1;
return (e.x<<16) | j;
}
e.nfree = 0;
print("ftl: unit %d:#%x nfree %d but not free in BAM\n", e.x, e.id, e.nfree);
}
if(++i >= ftl.nunit)
i = 0;
}while(i != ftl.lastx);
return 0;
}
mapblk(ftl : ref Ftl, bno : int) : (int, ref Terase, int)
{
v : int;
x : int;
if(bno < ftl.nblock){
v = ftl.vbm[bno];
if(v == 0 || v == ~0)
return (0, nil, 0);
x = v>>16;
if(x >= ftl.nunit || x == ftl.xfer || ftl.unit[x] == nil){
print("ftl: corrupt format: bad block mapping %d . unit #%x\n", bno, x);
return (0, nil, 0);
}
return (1, ftl.unit[x], v & 16rFFFF);
}
return (0, nil, 0);
}
eraseinit(ftl : ref Ftl, offset : int, id : int, nerase : int)
{
m : array of byte;
bam : array of byte;
i, nov : int;
nov = ((ftl.segsize/Bsize)*4 + BAMoffset + Bsize - 1)/Bsize; # number of overhead blocks (header, and BAM itself)
if(nov*Bsize >= ftl.segsize) {
fprint(stderr, "ftl -- too small for files");
exit;
}
eraseflash(ftl, offset);
m = array[ERASEHDRLEN] of byte;
if(m == nil) {
fprint(stderr, "nomem\n");
exit;
}
memset(m, 16rFF, len m);
m[O_LINKTUPLE+0] = byte 16r13;
m[O_LINKTUPLE+1] = byte 16r3;
memmove(m[O_LINKTUPLE+2:], array of byte "CIS", 3);
m[O_ORGTUPLE+0] = byte 16r46;
m[O_ORGTUPLE+1] = byte 16r57;
m[O_ORGTUPLE+2] = byte 16r00;
memmove(m[O_ORGTUPLE+3:], array of byte "FTL100\0", 7);
m[O_NXFER] = byte 1;
PUT4(m[O_NERASE:], nerase);
PUT2(m[O_ID:], id);
m[O_BSHIFT] = byte ftl.bshift;
m[O_ESHIFT] = byte ftl.eshift;
PUT2(m[O_PSTART:], 0);
PUT2(m[O_NUNITS:], ftl.nunit);
PUT4(m[O_PSIZE:], ftl.size - nov*Bsize);
PUT4(m[O_VBMBASE:], -1); # we always calculate the VBM (16rffffffff)
PUT2(m[O_NVBM:], 0);
m[O_FLAGS] = byte 0;
m[O_CODE] = byte 16rFF;
memmove(m[O_SERIAL:], array of byte "Inf1", 4);
PUT4(m[O_ALTOFFSET:], 0);
PUT4(m[O_BAMOFFSET:], BAMoffset);
putflash(ftl, offset, m, ERASEHDRLEN);
m = nil;
if(id == XferID)
return;
nov *= 4; # now bytes of BAM
bam = array[nov] of byte;
if(bam == nil) {
fprint(stderr, "nomem");
exit;
}
for(i=0; i<nov; i += 4)
PUT4(bam[i:], ControlBlock); # reserve them
putflash(ftl, offset+BAMoffset, bam, nov);
bam = nil;
}
eraseload(ftl : ref Ftl, x : int, offset : int) : ref Terase
{
m : array of byte;
e : ref Terase;
i, nbam : int;
bno, v : int;
m = array[ERASEHDRLEN] of byte;
if(m == nil) {
fprint(stderr, "nomem");
exit;
}
getflash(ftl, m, offset, ERASEHDRLEN);
if(memcmp(m[O_ORGTUPLE+3:], array of byte "FTL100\0", 7) != 0 ||
memcmp(m[O_SERIAL:], array of byte "Inf1", 4) != 0){
m = nil;
return nil;
}
e = ref Terase;
if(e == nil){
m = nil;
fprint(stderr, "nomem");
exit;
}
e.x = x;
e.id = GET2(m[O_ID:]);
e.offset = offset;
e.bamoffset = GET4(m[O_BAMOFFSET:]);
e.nerase = GET4(m[O_NERASE:]);
e.bamx = 0;
e.nfree = 0;
e.nused = 0;
e.ndead = 0;
e.nbad = 0;
m = nil;
if(e.bamoffset != BAMoffset){
e = nil;
return nil;
}
e.bamoffset += offset;
if(e.id == XferID || e.id == XferBusy){
e.bam = nil;
e.nbam = 0;
return e;
}
nbam = ftl.segsize/Bsize;
e.bam = array[4*nbam] of byte;
e.nbam = nbam;
getflash(ftl, e.bam, e.bamoffset, nbam*4);
# scan BAM to build VBM
e.bamx = 0;
for(i=0; i<nbam; i++){
v = GET4(e.bam[4*i:]);
if(v == Bwriting || v == Bdeleted)
e.ndead++;
else if(v == Bfree){
if(e.bamx == 0)
e.bamx = i;
e.nfree++;
ftl.nfree++;
}else{
case(v & BlockType){
ControlBlock =>
break;
DataBlock =>
# add to VBM
if(v & (1<<31))
break; # negative => VBM page, ignored
bno = BNO(v & ~BlockType);
if(i < ftl.fstart || bno >= ftl.nblock){
print("ftl: unit %d:#%x bad bam[%d]=#%x\n", e.x, e.id, i, v);
e.nbad++;
break;
}
ftl.vbm[bno] = (e.x<<16) | i;
e.nused++;
break;
ReplacePage =>
# replacement VBM page; ignored
break;
BadBlock =>
e.nbad++;
break;
* =>
print("ftl: unit %d:#%x bad bam[%d]=%x\n", e.x, e.id, i, v);
}
}
}
return e;
}
erasefree(e : ref Terase)
{
e.bam = nil;
e = nil;
}
eraseflash(ftl : ref Ftl, offset : int)
{
offset += ftl.base;
if(FTLDEBUG || ftl.trace || trace)
print("ftl: erase seg @#%x\n", offset);
memset(flashm[offset:], 16rff, secsize);
}
putflash(ftl : ref Ftl, offset : int, buf : array of byte, n : int)
{
offset += ftl.base;
if(ftl.trace || trace)
print("ftl: write(#%x, %d)\n", offset, n);
memmove(flashm[offset:], buf, n);
}
getflash(ftl : ref Ftl, buf : array of byte, offset : int, n : int)
{
offset += ftl.base;
if(ftl.trace || trace)
print("ftl: read(#%x, %d)\n", offset, n);
memmove(buf, flashm[offset:], n);
}
BUFSIZE : con 8192;
main(argv : list of string)
{
k, r, sz, offset : int = 0;
buf, buf1 : array of byte;
fd1, fd2 : ref FD;
if (len argv != 5) {
fprint(stderr, "usage: %s flashsize secsize kfsfile flashfile\n", hd argv);
exit;
}
flashsize = atoi(hd tl argv);
secsize = atoi(hd tl tl argv);
fd1 = open(hd tl tl tl argv, OREAD);
fd2 = create(hd tl tl tl tl argv, OWRITE, 8r644);
if (fd1 == nil || fd2 == nil) {
fprint(stderr, "bad io files\n");
exit;
}
if(secsize == 0 || secsize > flashsize || secsize&(secsize-1) || 0&(secsize-1) || flashsize == 0 || flashsize != Nolimit && flashsize&(secsize-1)) {
fprint(stderr, "ftl: bad sizes\n");
exit;
}
for(k=0; k<32 && (1<<k) != secsize; k++)
;
flashm = array[flashsize] of byte;
buf = array[BUFSIZE] of byte;
if (flashm == nil) {
fprint(stderr, "ftl: no mem for flash\n");
exit;
}
ftls = mkftl("FLASH", 0, Nolimit, k, "format");
for (;;) {
r = read(fd1, buf, BUFSIZE);
if (r <= 0)
break;
if (ftlwrite(buf, r, offset) != r) {
fprint(stderr, "ftl: ftlwrite failed - input file too big\n");
exit;
}
offset += r;
}
write(fd2, flashm, flashsize);
fd1 = fd2 = nil;
ftlstat(offset);
# ftls = mkftl("FLASH", 0, Nolimit, k, "init");
sz = offset;
offset = 0;
buf1 = array[BUFSIZE] of byte;
fd1 = open(hd tl tl tl argv, OREAD);
for (;;) {
r = read(fd1, buf1, BUFSIZE);
if (r <= 0)
break;
if (ftlread(buf, r, offset) != r) {
fprint(stderr, "ftl: ftlread failed\n");
exit;
}
if (memcmp(buf, buf1, r) != 0) {
fprint(stderr, "ftl: bad read\n");
exit;
}
offset += r;
}
fd1 = nil;
if (offset != sz) {
fprint(stderr, "ftl: bad final offset\n");
exit;
}
exit;
}
init(nil : ref Draw->Context, argl : list of string)
{
sys = load Sys Sys->PATH;
stderr = sys->fildes(2);
main(argl);
}
memset(d : array of byte, v : int, n : int)
{
for (i := 0; i < n; i++)
d[i] = byte v;
}
memmove(d : array of byte, s : array of byte, n : int)
{
d[0:] = s[0:n];
}
memcmp(s1 : array of byte, s2 : array of byte, n : int) : int
{
for (i := 0; i < n; i++) {
if (s1[i] < s2[i])
return -1;
if (s1[i] > s2[i])
return 1;
}
return 0;
}
atoi(s : string) : int
{
v : int;
base := 10;
n := len s;
neg := 0;
for (i := 0; i < n && (s[i] == ' ' || s[i] == '\t'); i++)
;
if (s[i] == '+' || s[i] == '-') {
if (s[i] == '-')
neg = 1;
i++;
}
if (n-i >= 2 && s[i] == '0' && s[i+1] == 'x') {
base = 16;
i += 2;
}
else if (n-i >= 1 && s[i] == '0') {
base = 8;
i++;
}
m := 0;
for(; i < n; i++) {
c := s[i];
case c {
'a' to 'z' =>
v = c - 'a' + 10;
'A' to 'Z' =>
v = c - 'A' + 10;
'0' to '9' =>
v = c - '0';
* =>
fprint(stderr, "ftl: bad character in number %s\n", s);
exit;
}
if(v >= base) {
fprint(stderr, "ftl: character too big for base in %s\n", s);
exit;
}
m = m * base + v;
}
if(neg)
m = -m;
return m;
}
# little endian
GET2(b : array of byte) : int
{
return ((int b[1]) << 8) | (int b[0]);
}
GET4(b : array of byte) : int
{
return ((int b[3]) << 24) | ((int b[2]) << 16) | ((int b[1]) << 8) | (int b[0]);
}
PUT2(b : array of byte, v : int)
{
b[1] = byte (v>>8);
b[0] = byte v;
}
PUT4(b : array of byte, v : int)
{
b[3] = byte (v>>24);
b[2] = byte (v>>16);
b[1] = byte (v>>8);
b[0] = byte v;
}