libvpx: Pull from upstream

source/libvpx/build/make/thumb.pm

 #!/usr/bin/perl
 ##
 ##  Copyright (c) 2013 The WebM project authors. All Rights Reserved.
 ##
 ##  Use of this source code is governed by a BSD-style license
 ##  that can be found in the LICENSE file in the root of the source
 ##  tree. An additional intellectual property rights grant can be found
 ##  in the file PATENTS.  All contributing project authors may
 ##  be found in the AUTHORS file in the root of the source tree.
 ##
 
 package thumb;
 
 sub FixThumbInstructions($$)
 {
     my $short_branches = $_[1];
     my $branch_shift_offset = $short_branches ? 1 : 0;
 
     # Write additions with shifts, such as "add r10, r11, lsl #8",
     # in three operand form, "add r10, r10, r11, lsl #8".
     s/(add\s+)(r\d+),\s*(r\d+),\s*(lsl #\d+)/$1$2, $2, $3, $4/g;
 
     # Convert additions with a non-constant shift into a sequence
     # with left shift, addition and a right shift (to restore the
     # register to the original value). Currently the right shift
     # isn't necessary in the code base since the values in these
-    # registers aren't used, but doing the shift for consitency.
+    # registers aren't used, but doing the shift for consistency.
     # This converts instructions such as "add r12, r12, r5, lsl r4"
     # into the sequence "lsl r5, r4", "add r12, r12, r5", "lsr r5, r4".
     s/^(\s*)(add)(\s+)(r\d+),\s*(r\d+),\s*(r\d+),\s*lsl (r\d+)/$1lsl$3$6, $7\n$1$2$3$4, $5, $6\n$1lsr$3$6, $7/g;
 
     # Convert loads with right shifts in the indexing into a
     # sequence of an add, load and sub. This converts
     # "ldrb r4, [r9, lr, asr #1]" into "add r9, r9, lr, asr #1",
     # "ldrb r9, [r9]", "sub r9, r9, lr, asr #1".
     s/^(\s*)(ldrb)(\s+)(r\d+),\s*\[(\w+),\s*(\w+),\s*(asr #\d+)\]/$1add $3$5, $5, $6, $7\n$1$2$3$4, [$5]\n$1sub $3$5, $5, $6, $7/g;
 
@@ skipping 23 matching lines @@
     # This assumes that r12 is free at this point.
     s/^(\s*)addlt(\s+)pc,\s*pc,\s*(\w+),\s*lsl\s*#(\d+)/$1itttt$2lt\n$1movlt.n$2r12, pc\n$1addlt.w$2r12, #12\n$1addlt.w$2r12, r12, $3, lsl #($4-$branch_shift_offset)\n$1movlt.n$2pc, r12/g;
 
     # Convert "mov pc, lr" into "bx lr", since the former only works
     # for switching from arm to thumb (and only in armv7), but not
     # from thumb to arm.
     s/mov(\s*)pc\s*,\s*lr/bx$1lr/g;
 }
 
 1;