--- /dev/null
+#!/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;
+ local $a0 = shift;
+ local $a1 = shift;
+ local $a2 = shift;
+ local $a3 = shift;
+ $code .= sprintf ("\t\t".$format."\n", $a0, $a1, $a2, $a3);
+}
+
+sub P {
+ local *code = shift;
+ local $format = shift;
+ local $a0 = shift;
+ local $a1 = shift;
+ local $a2 = shift;
+ local $a3 = shift;
+ $code .= sprintf ($format."\n", $a0, $a1, $a2, $a3);
+}
+
+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) {
+ &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", $label);
+ }
+}
+
+$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: */
+
+#ifdef L_ENDIAN
+# define BYTE_POS(n) (8 * (n))
+#else
+# define BYTE_POS(n) (56 - (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.
+*/
+
+#define MODSCHED_RC4(label) \\
+ { \\
+ 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 label; /* never taken */ \\
+ } ;; \\
+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]
+
+#ifdef _LP64
+ add InPrefetch = 0, InputBuffer
+ nop 0x0
+ }
+#else
+ ADDP InputBuffer = 0, InputBuffer
+ ADDP StateTable = 0, StateTable
+ }
+ ;;
+ {
+ ADDP InPrefetch = 0, InputBuffer
+ ADDP OutputBuffer = 0, OutputBuffer
+ nop 0x0
+ }
+#endif
+ ;;
+ {
+ .mmi
+ lfetch.nt1 [InPrefetch], 0x80
+ LKEY I[1] = [StateTable], SZ
+ mov OutPrefetch = OutputBuffer
+ } ;;
+ {
+ .mii
+ nop 0x0
+ nop 0x0
+ mov RetVal = r0
+ }
+ { // Return 0 if the input length is nonsensical
+ .mib
+ nop 0x0
+ cmp.ge L_NOK, L_OK = r0, DataLen
+ (L_NOK) br.ret.sptk.few rp
+ }
+ ;;
+ {
+ .mib
+ nop 0x0
+ cmp.eq L_NOK, L_OK = r0, InputBuffer
+ (L_NOK) br.ret.sptk.few rp
+ }
+ ;;
+ {
+ .mib
+ nop 0x0
+ cmp.eq L_NOK, L_OK = r0, OutputBuffer
+ (L_NOK) br.ret.sptk.few rp
+ }
+ ;;
+ {
+ .mib
+ nop 0x0
+ cmp.eq L_NOK, L_OK = r0, StateTable
+ (L_NOK) br.ret.sptk.few rp
+ }
+
+
+/* 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
+ lfetch.fault.nt1 [tmp0] // 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 = [StateTable], SZ
+ ADDP EndPtr = DataLen, InputBuffer
+ } ;;
+ {
+ .mmi
+ mov InPtr = InputBuffer
+ mov OutPtr = OutputBuffer
+ ADDP EndPtr = -1, EndPtr // Make it point to
+ // last data byte.
+ } ;;
+ {
+ .mii
+ mov KTable = StateTable
+ mov One = 1
+ .save ar.lc, LCSave
+ mov LCSave = ar.lc
+ .body
+ } ;;
+ {
+ .mmb
+ sub Remainder = 0, OutPtr
+ cmp.gtu pSmall, p0 = $threshold, DataLen
+(pSmall) br.cond.dpnt .rc4Remainder // Data too small for
+ // big loop.
+ } ;;
+ {
+ .mmi
+ and Remainder = 0x7, Remainder
+ ;;
+ cmp.eq pAligned, pUnaligned = Remainder, r0
+ nop 0x0
+ } ;;
+ {
+ .mmb
+(pUnaligned) add Remainder = -1, Remainder
+(pAligned) sub Remainder = EndPtr, InPtr
+(pAligned) br.cond.dptk.many .rc4Aligned
+ } ;;
+ {
+ .mmi
+ nop 0x0
+ nop 0x0
+ mov.i ar.lc = Remainder
+ }
+
+/* Do the initial few bytes via the compact, modulo-scheduled loop
+ until the output pointer is 8-byte-aligned. */
+
+ MODSCHED_RC4(.RC4AlignLoop)
+
+ {
+ .mib
+ sub Remainder = EndPtr, InPtr
+ zxt1 IFinal = IFinal
+ clrrrb // Clear CFM.rrb.pr so
+ ;; // next "mov pr.rot = N"
+ // does the right thing.
+ }
+ {
+ .mmi
+ mov I[1] = IFinal
+ nop 0x0
+ nop 0x0
+ } ;;
+
+
+.rc4Aligned:
+
+/*
+ Unrolled loop count = (Remainder - ($unroll_count+1)*$phases)/($unroll_count*$phases)
+ */
+
+ {
+ .mlx
+ add LoopCount = 1 - ($unroll_count + 1)*$phases, Remainder
+ movl Remainder = 0xaaaaaaaaaaaaaaab
+ } ;;
+ {
+ .mmi
+ setf.sig f6 = LoopCount // M2, M3 6 cyc
+ setf.sig f7 = Remainder // M2, M3 6 cyc
+ nop 0x0
+ } ;;
+ {
+ .mfb
+ nop 0x0
+ xmpy.hu f6 = f6, f7
+ nop 0x0
+ } ;;
+ {
+ .mmi
+ getf.sig LoopCount = f6 // M2 5 cyc
+ nop 0x0
+ nop 0x0
+ } ;;
+ {
+ .mmi
+ nop 0x0
+ nop 0x0
+ shr.u LoopCount = LoopCount, 4
+ } ;;
+ {
+ .mmi
+ nop 0x0
+ nop 0x0
+ mov.i ar.lc = LoopCount
+ } ;;
+
+/* Now comes the unrolled loop: */
+
+.rc4Prologue:
+___
+
+$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(.RC4RestLoop)
+
+ {
+ .mmi
+ nop 0x0
+ nop 0x0
+ zxt1 IFinal = IFinal
+ } ;;
+
+.rc4Complete:
+ {
+ .mmi
+ ADDP KTable = -2*SZ, KTable ;;
+ SKEY [KTable] = IFinal, SZ
+ mov ar.lc = LCSave
+ } ;;
+ {
+ .mii
+ nop 0x0
+ nop 0x0
+ add RetVal = 1, r0
+ }
+ {
+ .mib
+ SKEY [KTable] = J
+ mov pr = PRSave, 0x1FFFF
+ 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;