#! /usr/bin/env perl

# Copyright 2014-2020 The OpenSSL Project Authors. All Rights Reserved.

#

# Licensed under the OpenSSL license (the "License").  You may not use

# this file except in compliance with the License.  You can obtain a copy

# in the file LICENSE in the source distribution or at

# https://www.openssl.org/source/license.html

#

# ====================================================================

# Written by Andy Polyakov <appro@openssl.org> for the OpenSSL

# project. The module is, however, dual licensed under OpenSSL and

# CRYPTOGAMS licenses depending on where you obtain it. For further

# details see http://www.openssl.org/~appro/cryptogams/.

# ====================================================================

#

# RC4 for C64x+.

#

# April 2014

#

# RC4 subroutine processes one byte in 7.0 cycles, which is 3x faster

# than TI CGT-generated code. Loop is scheduled in such way that

# there is only one reference to memory in each cycle. This is done

# to avoid L1D memory banking conflicts, see SPRU871 TI publication

# for further details. Otherwise it should be possible to schedule

# the loop for iteration interval of 6...

($KEY,$LEN,$INP,$OUT)=("A4","B4","A6","B6");

($KEYA,$XX,$TY,$xx,$ONE,$ret)=map("A$_",(5,7,8,9,1,2));

($KEYB,$YY,$TX,$tx,$SUM,$dat)=map("B$_",(5,7,8,9,1,2));

$code.=<<___;

	.text

	.if	.ASSEMBLER_VERSION<7000000

	.asg	0,__TI_EABI__

	.endif

	.if	__TI_EABI__

	.nocmp

	.asg	RC4,_RC4

	.asg	RC4_set_key,_RC4_set_key

	.asg	RC4_options,_RC4_options

	.endif

	.global	_RC4

	.align	16

_RC4:

	.asmfunc

	MV	$LEN,B0

  [!B0]	BNOP	B3			; if (len==0) return;

||[B0]	ADD	$KEY,2,$KEYA

||[B0]	ADD	$KEY,2,$KEYB

  [B0]	MVK	1,$ONE

||[B0]	LDBU	*${KEYA}[-2],$XX	; key->x

  [B0]	LDBU	*${KEYB}[-1],$YY	; key->y

||	NOP	4

	ADD4	$ONE,$XX,$XX

	LDBU	*${KEYA}[$XX],$TX

||	MVC	$LEN,ILC

	NOP	4

;;==================================================

	SPLOOP	7

||	ADD4	$TX,$YY,$YY

	LDBU	*${KEYB}[$YY],$TY

||	MVD	$XX,$xx

||	ADD4	$ONE,$XX,$XX

	LDBU	*${KEYA}[$XX],$tx

	CMPEQ	$YY,$XX,B0

||	NOP	3

	STB	$TX,*${KEYB}[$YY]

||[B0]	ADD4	$TX,$YY,$YY

	STB	$TY,*${KEYA}[$xx]

||[!B0]	ADD4	$tx,$YY,$YY

||[!B0]	MVD	$tx,$TX

	ADD4	$TY,$TX,$SUM		; [0,0] $TX is not replaced by $tx yet!

||	NOP	2

	LDBU	*$INP++,$dat

||	NOP	2

	LDBU	*${KEYB}[$SUM],$ret

||	NOP	5

	XOR.L	$dat,$ret,$ret

	SPKERNEL

||	STB	$ret,*$OUT++

;;==================================================

	SUB4	$XX,$ONE,$XX

||	NOP	5

	STB	$XX,*${KEYA}[-2]	; key->x

||	SUB4	$YY,$TX,$YY

||	BNOP	B3

	STB	$YY,*${KEYB}[-1]	; key->y

||	NOP	5

	.endasmfunc

	.global	_RC4_set_key

	.align	16

_RC4_set_key:

	.asmfunc

	.if	.BIG_ENDIAN

	MVK	0x00000404,$ONE

||	MVK	0x00000203,B0

	MVKH	0x04040000,$ONE

||	MVKH	0x00010000,B0

	.else

	MVK	0x00000404,$ONE

||	MVK	0x00000100,B0

	MVKH	0x04040000,$ONE

||	MVKH	0x03020000,B0

	.endif

	ADD	$KEY,2,$KEYA

||	ADD	$KEY,2,$KEYB

||	ADD	$INP,$LEN,$ret		; end of input

	LDBU	*${INP}++,$dat

||	MVK	0,$TX

	STH	$TX,*${KEY}++		; key->x=key->y=0

||	MV	B0,A0

||	MVK	64-4,B0

;;==================================================

	SPLOOPD	1

||	MVC	B0,ILC

	STNW	A0,*${KEY}++

||	ADD4	$ONE,A0,A0

	SPKERNEL

;;==================================================

	MVK	0,$YY

||	MVK	0,$XX

	MVK	1,$ONE

||	MVK	256-1,B0

;;==================================================

	SPLOOPD	8

||	MVC	B0,ILC

	ADD4	$dat,$YY,$YY

||	CMPEQ	$INP,$ret,A0		; end of input?

	LDBU	*${KEYB}[$YY],$TY

||	MVD	$XX,$xx

||	ADD4	$ONE,$XX,$XX

	LDBU	*${KEYA}[$XX],$tx

||[A0]	SUB	$INP,$LEN,$INP		; rewind

	LDBU	*${INP}++,$dat

||	CMPEQ	$YY,$XX,B0

||	NOP	3

	STB	$TX,*${KEYB}[$YY]

||[B0]	ADD4	$TX,$YY,$YY

	STB	$TY,*${KEYA}[$xx]

||[!B0]	ADD4	$tx,$YY,$YY

||[!B0]	MV	$tx,$TX

	SPKERNEL

;;==================================================

	BNOP	B3,5

	.endasmfunc

	.global	_RC4_options

	.align	16

_RC4_options:

_rc4_options:

	.asmfunc

	BNOP	B3,1

	ADDKPC	_rc4_options,B4

	.if	__TI_EABI__

	MVKL	\$PCR_OFFSET(rc4_options,_rc4_options),A4

	MVKH	\$PCR_OFFSET(rc4_options,_rc4_options),A4

	.else

	MVKL	(rc4_options-_rc4_options),A4

	MVKH	(rc4_options-_rc4_options),A4

	.endif

	ADD	B4,A4,A4

	.endasmfunc

	.if	__TI_EABI__

	.sect	".text:rc4_options.const"

	.else

	.sect	".const:rc4_options"

	.endif

	.align	4

rc4_options:

	.cstring "rc4(sploop,char)"

	.cstring "RC4 for C64+, CRYPTOGAMS by <appro\@openssl.org>"

	.align	4

___

$output=pop;

open STDOUT,">$output";

print $code;

close STDOUT or die "error closing STDOUT: $!";