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-rw-r--r--security/nss/lib/freebl/arcfour-amd64-gas.s88
1 files changed, 88 insertions, 0 deletions
diff --git a/security/nss/lib/freebl/arcfour-amd64-gas.s b/security/nss/lib/freebl/arcfour-amd64-gas.s
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+# 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