openssl1.0/crypto/rc4/asm/rc4-ia64.pl

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2019-08-09 10:00:55 +02:00
#!/usr/bin/env perl
#
# ====================================================================
# Written by David Mosberger <David.Mosberger@acm.org> based on the
# Itanium optimized Crypto code which was released by HP Labs at
# http://www.hpl.hp.com/research/linux/crypto/.
#
# Copyright (c) 2005 Hewlett-Packard Development Company, L.P.
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
# This is a little helper program which generates a software-pipelined
# for RC4 encryption. The basic algorithm looks like this:
#
# for (counter = 0; counter < len; ++counter)
# {
# in = inp[counter];
# SI = S[I];
# J = (SI + J) & 0xff;
# SJ = S[J];
# T = (SI + SJ) & 0xff;
# S[I] = SJ, S[J] = SI;
# ST = S[T];
# outp[counter] = in ^ ST;
# I = (I + 1) & 0xff;
# }
#
# Pipelining this loop isn't easy, because the stores to the S[] array
# need to be observed in the right order. The loop generated by the
# code below has the following pipeline diagram:
#
# cycle
# | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 |11 |12 |13 |14 |15 |16 |17 |
# iter
# 1: xxx LDI xxx xxx xxx LDJ xxx SWP xxx LDT xxx xxx
# 2: xxx LDI xxx xxx xxx LDJ xxx SWP xxx LDT xxx xxx
# 3: xxx LDI xxx xxx xxx LDJ xxx SWP xxx LDT xxx xxx
#
# where:
# LDI = load of S[I]
# LDJ = load of S[J]
# SWP = swap of S[I] and S[J]
# LDT = load of S[T]
#
# Note that in the above diagram, the major trouble-spot is that LDI
# of the 2nd iteration is performed BEFORE the SWP of the first
# iteration. Fortunately, this is easy to detect (I of the 1st
# iteration will be equal to J of the 2nd iteration) and when this
# happens, we simply forward the proper value from the 1st iteration
# to the 2nd one. The proper value in this case is simply the value
# of S[I] from the first iteration (thanks to the fact that SWP
# simply swaps the contents of S[I] and S[J]).
#
# Another potential trouble-spot is in cycle 7, where SWP of the 1st
# iteration issues at the same time as the LDI of the 3rd iteration.
# However, thanks to IA-64 execution semantics, this can be taken
# care of simply by placing LDI later in the instruction-group than
# SWP. IA-64 CPUs will automatically forward the value if they
# detect that the SWP and LDI are accessing the same memory-location.
# The core-loop that can be pipelined then looks like this (annotated
# with McKinley/Madison issue port & latency numbers, assuming L1
# cache hits for the most part):
# operation: instruction: issue-ports: latency
# ------------------ ----------------------------- ------------- -------
# Data = *inp++ ld1 data = [inp], 1 M0-M1 1 cyc c0
# shladd Iptr = I, KeyTable, 3 M0-M3, I0, I1 1 cyc
# I = (I + 1) & 0xff padd1 nextI = I, one M0-M3, I0, I1 3 cyc
# ;;
# SI = S[I] ld8 SI = [Iptr] M0-M1 1 cyc c1 * after SWAP!
# ;;
# cmp.eq.unc pBypass = I, J * after J is valid!
# J = SI + J add J = J, SI M0-M3, I0, I1 1 cyc c2
# (pBypass) br.cond.spnt Bypass
# ;;
# ---------------------------------------------------------------------------------------
# J = J & 0xff zxt1 J = J I0, I1, 1 cyc c3
# ;;
# shladd Jptr = J, KeyTable, 3 M0-M3, I0, I1 1 cyc c4
# ;;
# SJ = S[J] ld8 SJ = [Jptr] M0-M1 1 cyc c5
# ;;
# ---------------------------------------------------------------------------------------
# T = (SI + SJ) add T = SI, SJ M0-M3, I0, I1 1 cyc c6
# ;;
# T = T & 0xff zxt1 T = T I0, I1 1 cyc
# S[I] = SJ st8 [Iptr] = SJ M2-M3 c7
# S[J] = SI st8 [Jptr] = SI M2-M3
# ;;
# shladd Tptr = T, KeyTable, 3 M0-M3, I0, I1 1 cyc c8
# ;;
# ---------------------------------------------------------------------------------------
# T = S[T] ld8 T = [Tptr] M0-M1 1 cyc c9
# ;;
# data ^= T xor data = data, T M0-M3, I0, I1 1 cyc c10
# ;;
# *out++ = Data ^ T dep word = word, data, 8, POS I0, I1 1 cyc c11
# ;;
# ---------------------------------------------------------------------------------------
# There are several points worth making here:
# - Note that due to the bypass/forwarding-path, the first two
# phases of the loop are strangly mingled together. In
# particular, note that the first stage of the pipeline is
# using the value of "J", as calculated by the second stage.
# - Each bundle-pair will have exactly 6 instructions.
# - Pipelined, the loop can execute in 3 cycles/iteration and
# 4 stages. However, McKinley/Madison can issue "st1" to
# the same bank at a rate of at most one per 4 cycles. Thus,
# instead of storing each byte, we accumulate them in a word
# and then write them back at once with a single "st8" (this
# implies that the setup code needs to ensure that the output
# buffer is properly aligned, if need be, by encoding the
# first few bytes separately).
# - There is no space for a "br.ctop" instruction. For this
# reason we can't use module-loop support in IA-64 and have
# to do a traditional, purely software-pipelined loop.
# - We can't replace any of the remaining "add/zxt1" pairs with
# "padd1" because the latency for that instruction is too high
# and would push the loop to the point where more bypasses
# would be needed, which we don't have space for.
# - The above loop runs at around 3.26 cycles/byte, or roughly
# 440 MByte/sec on a 1.5GHz Madison. This is well below the
# system bus bandwidth and hence with judicious use of
# "lfetch" this loop can run at (almost) peak speed even when
# the input and output data reside in memory. The
# max. latency that can be tolerated is (PREFETCH_DISTANCE *
# L2_LINE_SIZE * 3 cyc), or about 384 cycles assuming (at
# least) 1-ahead prefetching of 128 byte cache-lines. Note
# that we do NOT prefetch into L1, since that would only
# interfere with the S[] table values stored there. This is
# acceptable because there is a 10 cycle latency between
# load and first use of the input data.
# - We use a branch to out-of-line bypass-code of cycle-pressure:
# we calculate the next J, check for the need to activate the
# bypass path, and activate the bypass path ALL IN THE SAME
# CYCLE. If we didn't have these constraints, we could do
# the bypass with a simple conditional move instruction.
# Fortunately, the bypass paths get activated relatively
# infrequently, so the extra branches don't cost all that much
# (about 0.04 cycles/byte, measured on a 16396 byte file with
# random input data).
#
$phases = 4; # number of stages/phases in the pipelined-loop
$unroll_count = 6; # number of times we unrolled it
$pComI = (1 << 0);
$pComJ = (1 << 1);
$pComT = (1 << 2);
$pOut = (1 << 3);
$NData = 4;
$NIP = 3;
$NJP = 2;
$NI = 2;
$NSI = 3;
$NSJ = 2;
$NT = 2;
$NOutWord = 2;
#
# $threshold is the minimum length before we attempt to use the
# big software-pipelined loop. It MUST be greater-or-equal
# to:
# PHASES * (UNROLL_COUNT + 1) + 7
#
# The "+ 7" comes from the fact we may have to encode up to
# 7 bytes separately before the output pointer is aligned.
#
$threshold = (3 * ($phases * ($unroll_count + 1)) + 7);
sub I {
local *code = shift;
local $format = shift;
$code .= sprintf ("\t\t".$format."\n", @_);
}
sub P {
local *code = shift;
local $format = shift;
$code .= sprintf ($format."\n", @_);
}
sub STOP {
local *code = shift;
$code .=<<___;
;;
___
}
sub emit_body {
local *c = shift;
local *bypass = shift;
local ($iteration, $p) = @_;
local $i0 = $iteration;
local $i1 = $iteration - 1;
local $i2 = $iteration - 2;
local $i3 = $iteration - 3;
local $iw0 = ($iteration - 3) / 8;
local $iw1 = ($iteration > 3) ? ($iteration - 4) / 8 : 1;
local $byte_num = ($iteration - 3) % 8;
local $label = $iteration + 1;
local $pAny = ($p & 0xf) == 0xf;
local $pByp = (($p & $pComI) && ($iteration > 0));
$c.=<<___;
//////////////////////////////////////////////////
___
if (($p & 0xf) == 0) {
$c.="#ifdef HOST_IS_BIG_ENDIAN\n";
&I(\$c,"shr.u OutWord[%u] = OutWord[%u], 32;;",
$iw1 % $NOutWord, $iw1 % $NOutWord);
$c.="#endif\n";
&I(\$c, "st4 [OutPtr] = OutWord[%u], 4", $iw1 % $NOutWord);
return;
}
# Cycle 0
&I(\$c, "{ .mmi") if ($pAny);
&I(\$c, "ld1 Data[%u] = [InPtr], 1", $i0 % $NData) if ($p & $pComI);
&I(\$c, "padd1 I[%u] = One, I[%u]", $i0 % $NI, $i1 % $NI)if ($p & $pComI);
&I(\$c, "zxt1 J = J") if ($p & $pComJ);
&I(\$c, "}") if ($pAny);
&I(\$c, "{ .mmi") if ($pAny);
&I(\$c, "LKEY T[%u] = [T[%u]]", $i1 % $NT, $i1 % $NT) if ($p & $pOut);
&I(\$c, "add T[%u] = SI[%u], SJ[%u]",
$i0 % $NT, $i2 % $NSI, $i1 % $NSJ) if ($p & $pComT);
&I(\$c, "KEYADDR(IPr[%u], I[%u])", $i0 % $NIP, $i1 % $NI) if ($p & $pComI);
&I(\$c, "}") if ($pAny);
&STOP(\$c);
# Cycle 1
&I(\$c, "{ .mmi") if ($pAny);
&I(\$c, "SKEY [IPr[%u]] = SJ[%u]", $i2 % $NIP, $i1%$NSJ)if ($p & $pComT);
&I(\$c, "SKEY [JP[%u]] = SI[%u]", $i1 % $NJP, $i2%$NSI) if ($p & $pComT);
&I(\$c, "zxt1 T[%u] = T[%u]", $i0 % $NT, $i0 % $NT) if ($p & $pComT);
&I(\$c, "}") if ($pAny);
&I(\$c, "{ .mmi") if ($pAny);
&I(\$c, "LKEY SI[%u] = [IPr[%u]]", $i0 % $NSI, $i0%$NIP)if ($p & $pComI);
&I(\$c, "KEYADDR(JP[%u], J)", $i0 % $NJP) if ($p & $pComJ);
&I(\$c, "xor Data[%u] = Data[%u], T[%u]",
$i3 % $NData, $i3 % $NData, $i1 % $NT) if ($p & $pOut);
&I(\$c, "}") if ($pAny);
&STOP(\$c);
# Cycle 2
&I(\$c, "{ .mmi") if ($pAny);
&I(\$c, "LKEY SJ[%u] = [JP[%u]]", $i0 % $NSJ, $i0%$NJP) if ($p & $pComJ);
&I(\$c, "cmp.eq pBypass, p0 = I[%u], J", $i1 % $NI) if ($pByp);
&I(\$c, "dep OutWord[%u] = Data[%u], OutWord[%u], BYTE_POS(%u), 8",
$iw0%$NOutWord, $i3%$NData, $iw1%$NOutWord, $byte_num) if ($p & $pOut);
&I(\$c, "}") if ($pAny);
&I(\$c, "{ .mmb") if ($pAny);
&I(\$c, "add J = J, SI[%u]", $i0 % $NSI) if ($p & $pComI);
&I(\$c, "KEYADDR(T[%u], T[%u])", $i0 % $NT, $i0 % $NT) if ($p & $pComT);
&P(\$c, "(pBypass)\tbr.cond.spnt.many .rc4Bypass%u",$label)if ($pByp);
&I(\$c, "}") if ($pAny);
&STOP(\$c);
&P(\$c, ".rc4Resume%u:", $label) if ($pByp);
if ($byte_num == 0 && $iteration >= $phases) {
&I(\$c, "st8 [OutPtr] = OutWord[%u], 8",
$iw1 % $NOutWord) if ($p & $pOut);
if ($iteration == (1 + $unroll_count) * $phases - 1) {
if ($unroll_count == 6) {
&I(\$c, "mov OutWord[%u] = OutWord[%u]",
$iw1 % $NOutWord, $iw0 % $NOutWord);
}
&I(\$c, "lfetch.nt1 [InPrefetch], %u",
$unroll_count * $phases);
&I(\$c, "lfetch.excl.nt1 [OutPrefetch], %u",
$unroll_count * $phases);
&I(\$c, "br.cloop.sptk.few .rc4Loop");
}
}
if ($pByp) {
&P(\$bypass, ".rc4Bypass%u:", $label);
&I(\$bypass, "sub J = J, SI[%u]", $i0 % $NSI);
&I(\$bypass, "nop 0");
&I(\$bypass, "nop 0");
&I(\$bypass, ";;");
&I(\$bypass, "add J = J, SI[%u]", $i1 % $NSI);
&I(\$bypass, "mov SI[%u] = SI[%u]", $i0 % $NSI, $i1 % $NSI);
&I(\$bypass, "br.sptk.many .rc4Resume%u\n", $label);
&I(\$bypass, ";;");
}
}
$code=<<___;
.ident \"rc4-ia64.s, version 3.0\"
.ident \"Copyright (c) 2005 Hewlett-Packard Development Company, L.P.\"
#define LCSave r8
#define PRSave r9
/* Inputs become invalid once rotation begins! */
#define StateTable in0
#define DataLen in1
#define InputBuffer in2
#define OutputBuffer in3
#define KTable r14
#define J r15
#define InPtr r16
#define OutPtr r17
#define InPrefetch r18
#define OutPrefetch r19
#define One r20
#define LoopCount r21
#define Remainder r22
#define IFinal r23
#define EndPtr r24
#define tmp0 r25
#define tmp1 r26
#define pBypass p6
#define pDone p7
#define pSmall p8
#define pAligned p9
#define pUnaligned p10
#define pComputeI pPhase[0]
#define pComputeJ pPhase[1]
#define pComputeT pPhase[2]
#define pOutput pPhase[3]
#define RetVal r8
#define L_OK p7
#define L_NOK p8
#define _NINPUTS 4
#define _NOUTPUT 0
#define _NROTATE 24
#define _NLOCALS (_NROTATE - _NINPUTS - _NOUTPUT)
#ifndef SZ
# define SZ 4 // this must be set to sizeof(RC4_INT)
#endif
#if SZ == 1
# define LKEY ld1
# define SKEY st1
# define KEYADDR(dst, i) add dst = i, KTable
#elif SZ == 2
# define LKEY ld2
# define SKEY st2
# define KEYADDR(dst, i) shladd dst = i, 1, KTable
#elif SZ == 4
# define LKEY ld4
# define SKEY st4
# define KEYADDR(dst, i) shladd dst = i, 2, KTable
#else
# define LKEY ld8
# define SKEY st8
# define KEYADDR(dst, i) shladd dst = i, 3, KTable
#endif
#if defined(_HPUX_SOURCE) && !defined(_LP64)
# define ADDP addp4
#else
# define ADDP add
#endif
/* Define a macro for the bit number of the n-th byte: */
#if defined(_HPUX_SOURCE) || defined(B_ENDIAN)
# define HOST_IS_BIG_ENDIAN
# define BYTE_POS(n) (56 - (8 * (n)))
#else
# define BYTE_POS(n) (8 * (n))
#endif
/*
We must perform the first phase of the pipeline explicitly since
we will always load from the stable the first time. The br.cexit
will never be taken since regardless of the number of bytes because
the epilogue count is 4.
*/
/* MODSCHED_RC4 macro was split to _PROLOGUE and _LOOP, because HP-UX
assembler failed on original macro with syntax error. <appro> */
#define MODSCHED_RC4_PROLOGUE \\
{ \\
ld1 Data[0] = [InPtr], 1; \\
add IFinal = 1, I[1]; \\
KEYADDR(IPr[0], I[1]); \\
} ;; \\
{ \\
LKEY SI[0] = [IPr[0]]; \\
mov pr.rot = 0x10000; \\
mov ar.ec = 4; \\
} ;; \\
{ \\
add J = J, SI[0]; \\
zxt1 I[0] = IFinal; \\
br.cexit.spnt.few .+16; /* never taken */ \\
} ;;
#define MODSCHED_RC4_LOOP(label) \\
label: \\
{ .mmi; \\
(pComputeI) ld1 Data[0] = [InPtr], 1; \\
(pComputeI) add IFinal = 1, I[1]; \\
(pComputeJ) zxt1 J = J; \\
}{ .mmi; \\
(pOutput) LKEY T[1] = [T[1]]; \\
(pComputeT) add T[0] = SI[2], SJ[1]; \\
(pComputeI) KEYADDR(IPr[0], I[1]); \\
} ;; \\
{ .mmi; \\
(pComputeT) SKEY [IPr[2]] = SJ[1]; \\
(pComputeT) SKEY [JP[1]] = SI[2]; \\
(pComputeT) zxt1 T[0] = T[0]; \\
}{ .mmi; \\
(pComputeI) LKEY SI[0] = [IPr[0]]; \\
(pComputeJ) KEYADDR(JP[0], J); \\
(pComputeI) cmp.eq.unc pBypass, p0 = I[1], J; \\
} ;; \\
{ .mmi; \\
(pComputeJ) LKEY SJ[0] = [JP[0]]; \\
(pOutput) xor Data[3] = Data[3], T[1]; \\
nop 0x0; \\
}{ .mmi; \\
(pComputeT) KEYADDR(T[0], T[0]); \\
(pBypass) mov SI[0] = SI[1]; \\
(pComputeI) zxt1 I[0] = IFinal; \\
} ;; \\
{ .mmb; \\
(pOutput) st1 [OutPtr] = Data[3], 1; \\
(pComputeI) add J = J, SI[0]; \\
br.ctop.sptk.few label; \\
} ;;
.text
.align 32
.type RC4, \@function
.global RC4
.proc RC4
.prologue
RC4:
{
.mmi
alloc r2 = ar.pfs, _NINPUTS, _NLOCALS, _NOUTPUT, _NROTATE
.rotr Data[4], I[2], IPr[3], SI[3], JP[2], SJ[2], T[2], \\
OutWord[2]
.rotp pPhase[4]
ADDP InPrefetch = 0, InputBuffer
ADDP KTable = 0, StateTable
}
{
.mmi
ADDP InPtr = 0, InputBuffer
ADDP OutPtr = 0, OutputBuffer
mov RetVal = r0
}
;;
{
.mmi
lfetch.nt1 [InPrefetch], 0x80
ADDP OutPrefetch = 0, OutputBuffer
}
{ // Return 0 if the input length is nonsensical
.mib
ADDP StateTable = 0, StateTable
cmp.ge.unc L_NOK, L_OK = r0, DataLen
(L_NOK) br.ret.sptk.few rp
}
;;
{
.mib
cmp.eq.or L_NOK, L_OK = r0, InPtr
cmp.eq.or L_NOK, L_OK = r0, OutPtr
nop 0x0
}
{
.mib
cmp.eq.or L_NOK, L_OK = r0, StateTable
nop 0x0
(L_NOK) br.ret.sptk.few rp
}
;;
LKEY I[1] = [KTable], SZ
/* Prefetch the state-table. It contains 256 elements of size SZ */
#if SZ == 1
ADDP tmp0 = 1*128, StateTable
#elif SZ == 2
ADDP tmp0 = 3*128, StateTable
ADDP tmp1 = 2*128, StateTable
#elif SZ == 4
ADDP tmp0 = 7*128, StateTable
ADDP tmp1 = 6*128, StateTable
#elif SZ == 8
ADDP tmp0 = 15*128, StateTable
ADDP tmp1 = 14*128, StateTable
#endif
;;
#if SZ >= 8
lfetch.fault.nt1 [tmp0], -256 // 15
lfetch.fault.nt1 [tmp1], -256;;
lfetch.fault.nt1 [tmp0], -256 // 13
lfetch.fault.nt1 [tmp1], -256;;
lfetch.fault.nt1 [tmp0], -256 // 11
lfetch.fault.nt1 [tmp1], -256;;
lfetch.fault.nt1 [tmp0], -256 // 9
lfetch.fault.nt1 [tmp1], -256;;
#endif
#if SZ >= 4
lfetch.fault.nt1 [tmp0], -256 // 7
lfetch.fault.nt1 [tmp1], -256;;
lfetch.fault.nt1 [tmp0], -256 // 5
lfetch.fault.nt1 [tmp1], -256;;
#endif
#if SZ >= 2
lfetch.fault.nt1 [tmp0], -256 // 3
lfetch.fault.nt1 [tmp1], -256;;
#endif
{
.mii
lfetch.fault.nt1 [tmp0] // 1
add I[1]=1,I[1];;
zxt1 I[1]=I[1]
}
{
.mmi
lfetch.nt1 [InPrefetch], 0x80
lfetch.excl.nt1 [OutPrefetch], 0x80
.save pr, PRSave
mov PRSave = pr
} ;;
{
.mmi
lfetch.excl.nt1 [OutPrefetch], 0x80
LKEY J = [KTable], SZ
ADDP EndPtr = DataLen, InPtr
} ;;
{
.mmi
ADDP EndPtr = -1, EndPtr // Make it point to
// last data byte.
mov One = 1
.save ar.lc, LCSave
mov LCSave = ar.lc
.body
} ;;
{
.mmb
sub Remainder = 0, OutPtr
cmp.gtu pSmall, p0 = $threshold, DataLen
(pSmall) br.cond.dpnt .rc4Remainder // Data too small for
// big loop.
} ;;
{
.mmi
and Remainder = 0x7, Remainder
;;
cmp.eq pAligned, pUnaligned = Remainder, r0
nop 0x0
} ;;
{
.mmb
.pred.rel "mutex",pUnaligned,pAligned
(pUnaligned) add Remainder = -1, Remainder
(pAligned) sub Remainder = EndPtr, InPtr
(pAligned) br.cond.dptk.many .rc4Aligned
} ;;
{
.mmi
nop 0x0
nop 0x0
mov.i ar.lc = Remainder
}
/* Do the initial few bytes via the compact, modulo-scheduled loop
until the output pointer is 8-byte-aligned. */
MODSCHED_RC4_PROLOGUE
MODSCHED_RC4_LOOP(.RC4AlignLoop)
{
.mib
sub Remainder = EndPtr, InPtr
zxt1 IFinal = IFinal
clrrrb // Clear CFM.rrb.pr so
;; // next "mov pr.rot = N"
// does the right thing.
}
{
.mmi
mov I[1] = IFinal
nop 0x0
nop 0x0
} ;;
.rc4Aligned:
/*
Unrolled loop count = (Remainder - ($unroll_count+1)*$phases)/($unroll_count*$phases)
*/
{
.mlx
add LoopCount = 1 - ($unroll_count + 1)*$phases, Remainder
movl Remainder = 0xaaaaaaaaaaaaaaab
} ;;
{
.mmi
setf.sig f6 = LoopCount // M2, M3 6 cyc
setf.sig f7 = Remainder // M2, M3 6 cyc
nop 0x0
} ;;
{
.mfb
nop 0x0
xmpy.hu f6 = f6, f7
nop 0x0
} ;;
{
.mmi
getf.sig LoopCount = f6;; // M2 5 cyc
nop 0x0
shr.u LoopCount = LoopCount, 4
} ;;
{
.mmi
nop 0x0
nop 0x0
mov.i ar.lc = LoopCount
} ;;
/* Now comes the unrolled loop: */
.rc4Prologue:
___
$iteration = 0;
# Generate the prologue:
$predicates = 1;
for ($i = 0; $i < $phases; ++$i) {
&emit_body (\$code, \$bypass, $iteration++, $predicates);
$predicates = ($predicates << 1) | 1;
}
$code.=<<___;
.rc4Loop:
___
# Generate the body:
for ($i = 0; $i < $unroll_count*$phases; ++$i) {
&emit_body (\$code, \$bypass, $iteration++, $predicates);
}
$code.=<<___;
.rc4Epilogue:
___
# Generate the epilogue:
for ($i = 0; $i < $phases; ++$i) {
$predicates <<= 1;
&emit_body (\$code, \$bypass, $iteration++, $predicates);
}
$code.=<<___;
{
.mmi
lfetch.nt1 [EndPtr] // fetch line with last byte
mov IFinal = I[1]
nop 0x0
}
.rc4Remainder:
{
.mmi
sub Remainder = EndPtr, InPtr // Calculate
// # of bytes
// left - 1
nop 0x0
nop 0x0
} ;;
{
.mib
cmp.eq pDone, p0 = -1, Remainder // done already?
mov.i ar.lc = Remainder
(pDone) br.cond.dptk.few .rc4Complete
}
/* Do the remaining bytes via the compact, modulo-scheduled loop */
MODSCHED_RC4_PROLOGUE
MODSCHED_RC4_LOOP(.RC4RestLoop)
.rc4Complete:
{
.mmi
add KTable = -SZ, KTable
add IFinal = -1, IFinal
mov ar.lc = LCSave
} ;;
{
.mii
SKEY [KTable] = J,-SZ
zxt1 IFinal = IFinal
mov pr = PRSave, 0x1FFFF
} ;;
{
.mib
SKEY [KTable] = IFinal
add RetVal = 1, r0
br.ret.sptk.few rp
} ;;
___
# Last but not least, emit the code for the bypass-code of the unrolled loop:
$code.=$bypass;
$code.=<<___;
.endp RC4
___
print $code;