1 @/* 2 @ ** Copyright 2003-2010, VisualOn, Inc. 3 @ ** 4 @ ** Licensed under the Apache License, Version 2.0 (the "License"); 5 @ ** you may not use this file except in compliance with the License. 6 @ ** You may obtain a copy of the License at 7 @ ** 8 @ ** http://www.apache.org/licenses/LICENSE-2.0 9 @ ** 10 @ ** Unless required by applicable law or agreed to in writing, software 11 @ ** distributed under the License is distributed on an "AS IS" BASIS, 12 @ ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 @ ** See the License for the specific language governing permissions and 14 @ ** limitations under the License. 15 @ */ 16 @ 17 @void Scale_sig( 18 @ Word16 x[], /* (i/o) : signal to scale */ 19 @ Word16 lg, /* (i) : size of x[] */ 20 @ Word16 exp /* (i) : exponent: x = round(x << exp) */ 21 @ ) 22 @ 23 @r0 --- x[] 24 @r1 --- lg 25 @r2 --- exp 26 27 .section .text 28 .global Scale_sig_opt 29 30 Scale_sig_opt: 31 32 STMFD r13!, {r4 - r12, r14} 33 SUB r3, r1, #1 @i = lg - 1 34 CMP r2, #0 @Compare exp and 0 35 RSB r7, r2, #0 @exp = -exp 36 ADD r10, r2, #16 @16 + exp 37 ADD r4, r0, r3, LSL #1 @x[i] address 38 MOV r8, #0x7fffffff 39 MOV r9, #0x8000 40 BLE LOOP2 41 42 LOOP1: 43 44 LDRSH r5, [r4] @load x[i] 45 MOV r12, r5, LSL r10 46 TEQ r5, r12, ASR r10 47 EORNE r12, r8, r5, ASR #31 48 SUBS r3, r3, #1 49 QADD r11, r12, r9 50 MOV r12, r11, ASR #16 51 STRH r12, [r4], #-2 52 BGE LOOP1 53 BL The_end 54 55 LOOP2: 56 57 LDRSH r5, [r4] @load x[i] 58 MOV r6, r5, LSL #16 @L_tmp = x[i] << 16 59 MOV r5, r6, ASR r7 @L_tmp >>= exp 60 QADD r11, r5, r9 61 MOV r12, r11, ASR #16 62 SUBS r3, r3, #1 63 STRH r12, [r4], #-2 64 BGE LOOP2 65 66 The_end: 67 LDMFD r13!, {r4 - r12, r15} 68 69 @ENDFUNC 70 .END 71 72 73 74 75 76
