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-rw-r--r--apps/codecs/lib/udiv32_armv4.S48
1 files changed, 5 insertions, 43 deletions
diff --git a/apps/codecs/lib/udiv32_armv4.S b/apps/codecs/lib/udiv32_armv4.S
index 6921c7fbd1..d7054e1ba4 100644
--- a/apps/codecs/lib/udiv32_armv4.S
+++ b/apps/codecs/lib/udiv32_armv4.S
@@ -104,20 +104,6 @@
104 @subls \dividend, \dividend, \divisor @ correct remainder not needed 104 @subls \dividend, \dividend, \divisor @ correct remainder not needed
105.endm 105.endm
106 106
107.macro ARM_DIV2_ORDER divisor, order
108
109 @ There's exactly one bit set in the divisor, so ffs() can be used
110 @ This is the ffs algorithm devised by D.Seal and posted to
111 @ comp.sys.arm on 16 Feb 1994.
112 adr \order, L_ffs_table
113 orr \divisor, \divisor, \divisor, lsl #4 @ = X * 0x11
114 orr \divisor, \divisor, \divisor, lsl #6 @ = X * 0x451
115 rsb \divisor, \divisor, \divisor, lsl #16 @ = X * 0x0450fbaf
116
117 ldrb \order, [\order, \divisor, lsr #26]
118.endm
119
120
121#ifdef USE_IRAM 107#ifdef USE_IRAM
122 .section .icode,"ax",%progbits 108 .section .icode,"ax",%progbits
123#else 109#else
@@ -128,45 +114,21 @@
128 .type udiv32_arm,%function 114 .type udiv32_arm,%function
129 115
130udiv32_arm: 116udiv32_arm:
131 subs r2, r1, #1 117 cmp r1, #0
132 bxeq lr 118 beq 20f
133 bcc 20f
134 cmp r0, r1
135 bls 10f
136 tst r1, r2
137 beq 30f
138 tst r0, r0 119 tst r0, r0
139 /* High bit must be unset, otherwise use ARM_DIV_32_BODY. High bit of 120 /* High bit must be unset, otherwise use ARM_DIV_32_BODY. High bit of
140 divisor is also unset dividend has been tested to be >= divisor. 121 divisor is also unset dividend has been tested to be >= divisor.
141 */ 122 */
142 bmi 5f 123 bmi 10f
143 ARM_DIV_31_BODY r0, r1, r2, r3, ip, r0 124 ARM_DIV_31_BODY r0, r1, r2, r3, ip, r0
144 bx lr 125 bx lr
145 126
1465: 12710:
147 ARM_DIV_32_BODY r0, r1, r2, r3 128 ARM_DIV_32_BODY r0, r1, r2, r3
148 mov r0, r2 129 mov r0, r2
149 bx lr 130 bx lr
150 131
15110:
152 moveq r0, #1
15320: 13220:
154 movne r0, #0 133 movne r0, #0
155 bx lr 134 bx lr \ No newline at end of file
156
15730:
158 ARM_DIV2_ORDER r1, r2
159 mov r0, r0, lsr r2
160 bx lr
161
162L_ffs_table:
163 @ 0 1 2 3 4 5 6 7
164 @----------------------------------------------
165 .byte 32, 0, 1, 12, 2, 6, 0, 13 @ 0- 7
166 .byte 3, 0, 7, 0, 0, 0, 0, 14 @ 8-15
167 .byte 10, 4, 0, 0, 8, 0, 0, 25 @ 16-23
168 .byte 0, 0, 0, 0, 0, 21, 27, 15 @ 24-31
169 .byte 31, 11, 5, 0, 0, 0, 0, 0 @ 32-39
170 .byte 9, 0, 0, 24, 0, 0, 20, 26 @ 40-47
171 .byte 30, 0, 0, 0, 0, 23, 0, 19 @ 48-55
172 .byte 29, 0, 22, 18, 28, 17, 16, 0 @ 56-63