shithub: libvpx

Info  •  Files  •  Log  •  Branches

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

--- a/build/make/ads2armasm_ms.pl

+++ b/build/make/ads2armasm_ms.pl

@@ -28,7 +28,7 @@

     s/qsubaddx/qsax/i;

     s/qaddsubx/qasx/i;

-    thumb::FixThumbInstructions($_);

+    thumb::FixThumbInstructions($_, 1);

     s/ldrneb/ldrbne/i;

     s/ldrneh/ldrhne/i;

--- a/build/make/ads2gas.pl

+++ b/build/make/ads2gas.pl

@@ -183,7 +183,7 @@

     s/(vtbl.\d+\s+[^,]+),([^,]+)/$1,\{$2\}/g;

     if ($thumb) {

-        thumb::FixThumbInstructions($_);

+        thumb::FixThumbInstructions($_, 0);

     }

     # eabi_attributes numerical equivalents can be found in the

--- a/build/make/thumb.pm

+++ b/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 @@

     # "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

-- 

⑨