thumb: Add a parameter for specifying a shift offset for the pc addition conversion

The branch instructions are encoded as 16 bit instructions
by the microsoft assembler, while they are encoded as 32 bit
instructions by gnu binutils.

Change-Id: I622b9025df3520c08eef8447df078f5517fb4b67

build/make/ads2armasm_ms.pl

@@ -28,7 +28,7 @@ while (<STDIN>)
     s/qsubaddx/qsax/i;
     s/qaddsubx/qasx/i;
 
-    thumb::FixThumbInstructions($_);
+    thumb::FixThumbInstructions($_, 1);
 
     s/ldrneb/ldrbne/i;
     s/ldrneh/ldrhne/i;

build/make/ads2gas.pl

@@ -183,7 +183,7 @@ while (<STDIN>)
     s/(vtbl.\d+\s+[^,]+),([^,]+)/$1,\{$2\}/g;
 
     if ($thumb) {
-        thumb::FixThumbInstructions($_);
+        thumb::FixThumbInstructions($_, 0);
     }
 
     # eabi_attributes numerical equivalents can be found in the

build/make/thumb.pm

@@ -11,8 +11,11 @@
 
 package thumb;
 
-sub FixThumbInstructions($)
+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, $4/g;
@@ -56,7 +59,7 @@ sub FixThumbInstructions($)
     # "itttt lt", "movlt.n r12, pc", "addlt.w r12, #12",
     # "addlt.w r12, r12, r3, lsl #2", "movlt.n pc, r12".
     # 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\n$1movlt.n$2pc, r12/g;
+    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