From: Andy Polyakov Date: Mon, 18 Jul 2005 16:55:52 +0000 (+0000) Subject: Unrolled RC4 IA-64 loop gives 40% improvement over current assembler X-Git-Tag: OpenSSL_0_9_8k^2~1928 X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff_plain;h=02703c74a4c10f3848cdd5e7ff5196ab45c7e67e Unrolled RC4 IA-64 loop gives 40% improvement over current assembler implementation [as predicted]. Submitted by: David Mosberger Obtained from: http://www.hpl.hp.com/research/linux/crypto/ --- diff --git a/crypto/rc4/asm/rc4-ia64.pl b/crypto/rc4/asm/rc4-ia64.pl new file mode 100644 index 0000000000..330b95f7dd --- /dev/null +++ b/crypto/rc4/asm/rc4-ia64.pl @@ -0,0 +1,788 @@ +#!/usr/bin/env perl +# +# ==================================================================== +# Written by David Mosberger 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;