import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

security/nss/lib/freebl/arcfour-amd64-gas.s

@@ -0,0 +1,88 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# ** ARCFOUR implementation optimized for AMD64.
+# **
+# ** The throughput achieved by this code is about 320 MBytes/sec, on
+# ** a 1.8 GHz AMD Opteron (rev C0) processor.
+
+.text
+.align 16
+.globl ARCFOUR
+.type ARCFOUR,@function
+ARCFOUR:
+	pushq	%rbp
+	pushq	%rbx
+	movq	%rdi,		%rbp	# key = ARG(key)
+	movq	%rsi,		%rbx	# rbx = ARG(len)
+	movq	%rdx,		%rsi	# in = ARG(in)
+	movq	%rcx,		%rdi	# out = ARG(out)
+	movq	(%rbp),		%rcx	# x = key->x
+	movq	8(%rbp),	%rdx	# y = key->y
+	addq	$16,		%rbp	# d = key->data
+	incq	%rcx			# x++
+	andq	$255,		%rcx	# x &= 0xff
+	leaq	-8(%rbx,%rsi),	%rbx	# rbx = in+len-8
+	movq	%rbx,		%r9	# tmp = in+len-8
+	movq	0(%rbp,%rcx,8),	%rax	# tx = d[x]
+	cmpq	%rsi,		%rbx	# cmp in with in+len-8
+	jl	.Lend			# jump if (in+len-8 < in)
+
+.Lstart:
+	addq	$8,		%rsi		# increment in
+	addq	$8,		%rdi		# increment out
+
+	# generate the next 8 bytes of the rc4 stream into %r8
+	movq	$8,		%r11		# byte counter
+1:	addb	%al,		%dl		# y += tx
+	movl	0(%rbp,%rdx,8),	%ebx		# ty = d[y]
+	movl	%ebx,		0(%rbp,%rcx,8)	# d[x] = ty
+	addb	%al,		%bl		# val = ty + tx
+	movl	%eax,		0(%rbp,%rdx,8)	# d[y] = tx
+	incb	%cl				# x++		(NEXT ROUND)
+	movl	0(%rbp,%rcx,8),	%eax		# tx = d[x]	(NEXT ROUND)
+	movb	0(%rbp,%rbx,8),	%r8b		# val = d[val]
+	decb	%r11b
+	rorq	$8,		%r8		# (ror does not change ZF)
+	jnz 	1b
+
+	# xor 8 bytes
+	xorq	-8(%rsi),	%r8
+	cmpq	%r9,		%rsi		# cmp in+len-8 with in
+	movq	%r8,		-8(%rdi)
+	jle	.Lstart				# jump if (in <= in+len-8)
+
+.Lend:
+	addq	$8,		%r9		# tmp = in+len
+
+	# handle the last bytes, one by one
+1:	cmpq	%rsi,		%r9		# cmp in with in+len
+	jle	.Lfinished			# jump if (in+len <= in)
+	addb	%al,		%dl		# y += tx
+	movl	0(%rbp,%rdx,8),	%ebx		# ty = d[y]
+	movl	%ebx,		0(%rbp,%rcx,8)	# d[x] = ty
+	addb	%al,		%bl		# val = ty + tx
+	movl	%eax,		0(%rbp,%rdx,8)	# d[y] = tx
+	incb	%cl				# x++		(NEXT ROUND)
+	movl	0(%rbp,%rcx,8),	%eax		# tx = d[x]	(NEXT ROUND)
+	movb	0(%rbp,%rbx,8),	%r8b		# val = d[val]
+	xorb	(%rsi),		%r8b		# xor 1 byte
+	movb	%r8b,		(%rdi)
+	incq	%rsi				# in++
+	incq	%rdi				# out++
+	jmp 1b
+
+.Lfinished:
+	decq	%rcx				# x--
+	movb	%dl,		-8(%rbp)	# key->y = y
+	movb	%cl,		-16(%rbp)	# key->x = x
+	popq	%rbx
+	popq	%rbp
+	ret
+.L_ARCFOUR_end:
+.size ARCFOUR,.L_ARCFOUR_end-ARCFOUR
+
+# Magic indicating no need for an executable stack
+.section .note.GNU-stack,"",@progbits
+.previous