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Diffstat (limited to 'core/cortex-m0/thumb_case.S')
| -rw-r--r-- | core/cortex-m0/thumb_case.S | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/core/cortex-m0/thumb_case.S b/core/cortex-m0/thumb_case.S new file mode 100644 index 0000000000..1229988d9f --- /dev/null +++ b/core/cortex-m0/thumb_case.S @@ -0,0 +1,35 @@ +/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved. + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE file. + * + * Thumb mode toolchain helpers for compact switch/case statement. + */ + +#include "config.h" + +.text + +.syntax unified +.code 16 + +/* + * Helper for compact switch + * + * r0: the table index + * lr: the table base address + * + * r0 and lr must be PRESERVED. + * r12 can be clobbered. + */ +.global __gnu_thumb1_case_uqi +.thumb_func +__gnu_thumb1_case_uqi: + push {r1} + mov r1, lr + lsrs r1, r1, #1 + lsls r1, r1, #1 + ldrb r1, [r1, r0] + lsls r1, r1, #1 + add lr, lr, r1 + pop {r1} + bx lr |