From c4f637077eb4504aa0109aac9983dfe85e5b2afb Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Mon, 26 Sep 2016 15:51:45 -0700 Subject: [PATCH] MdePkg/BaseMemoryLibOptDxe ARM: fix Thumb-2 bug in ScanMem() The ARM ScanMem() in BaseMemoryLibOptDxe contains code from the open source cortex-strings library, and inherited a bug from it where the conditional execution of a sequence of instructions is erroneously made dependent on the same condition. Since the final 'addeq' is supposed to be dependent on the preceding 'tsteq' instruction, they cannot be part of the same IT block. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Ard Biesheuvel Reviewed-by: Liming Gao --- MdePkg/Library/BaseMemoryLibOptDxe/Arm/ScanMem.S | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/MdePkg/Library/BaseMemoryLibOptDxe/Arm/ScanMem.S b/MdePkg/Library/BaseMemoryLibOptDxe/Arm/ScanMem.S index dc0e74e865..1c269547b0 100644 --- a/MdePkg/Library/BaseMemoryLibOptDxe/Arm/ScanMem.S +++ b/MdePkg/Library/BaseMemoryLibOptDxe/Arm/ScanMem.S @@ -134,11 +134,12 @@ ASM_PFX(InternalMemScanMem8): bne 61f adds r0, r0, #1 tst r5, #CHARTSTMASK(1) // 2nd character - ittt eq - addeq r0, r0 ,#1 - tsteq r5, #(3 << 15) // 2nd & 3rd character + bne 61f + adds r0, r0 ,#1 + tst r5, #(3 << 15) // 2nd & 3rd character // If not the 3rd must be the last one - addeq r0, r0, #1 + it eq + addeq.n r0, r0, #1 61: pop {r4-r7} -- 2.39.2