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authorThomas Martitz <kugel@rockbox.org>2012-01-08 00:22:58 +0100
committerThomas Martitz <kugel@rockbox.org>2012-01-22 18:46:45 +0100
commitc94cf3b8885c8a9e192b95125ce4b8470a1aa3c3 (patch)
tree6ca83258616b00428b58e1e31c10dce020fbc310 /firmware/asm
parent5e9b62cd8ad4d38c7ca43c916b5bc831454bc267 (diff)
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Move optimized ffs to firmware/asm, using the new automatic-asm-picking infrastructure.
Change-Id: I5e7bdc8be7de50ef604c16078857fff1b84650dc
Diffstat (limited to 'firmware/asm')
-rw-r--r--firmware/asm/SOURCES1
-rw-r--r--firmware/asm/arm/ffs.S75
-rw-r--r--firmware/asm/ffs.c56
-rw-r--r--firmware/asm/m68k/ffs.S78
-rw-r--r--firmware/asm/mips/ffs.S59
5 files changed, 269 insertions, 0 deletions
diff --git a/firmware/asm/SOURCES b/firmware/asm/SOURCES
index f56d99a7de..23563d11d8 100644
--- a/firmware/asm/SOURCES
+++ b/firmware/asm/SOURCES
@@ -1,3 +1,4 @@
+ffs.c
memset16.c
#if (CONFIG_PLATFORM & PLATFORM_NATIVE) || defined(HAVE_ROCKBOX_C_LIBRARY)
memcpy.c
diff --git a/firmware/asm/arm/ffs.S b/firmware/asm/arm/ffs.S
new file mode 100644
index 0000000000..4e912c5317
--- /dev/null
+++ b/firmware/asm/arm/ffs.S
@@ -0,0 +1,75 @@
+/***************************************************************************
+ * __________ __ ___.
+ * Open \______ \ ____ ____ | | _\_ |__ _______ ___
+ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
+ * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
+ * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
+ * \/ \/ \/ \/ \/
+ * $Id$
+ *
+ * Copyright (C) 2008 by Michael Sevakis
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+ #include "config.h"
+
+/****************************************************************************
+ * int find_first_set_bit(uint32_t val);
+ *
+ * Find the index of the least significant set bit in the 32-bit word.
+ *
+ * return values:
+ * 0 - bit 0 is set
+ * 1 - bit 1 is set
+ * ...
+ * 31 - bit 31 is set
+ * 32 - no bits set
+ ****************************************************************************/
+ .align 2
+ .global find_first_set_bit
+ .type find_first_set_bit,%function
+find_first_set_bit:
+ @ Standard trick to isolate bottom bit in r0 or 0 if r0 = 0 on entry
+ rsb r2, r0, #0 @ r1 = r0 & -r0
+ ands r1, r0, r2 @
+
+ @ now r1 has at most one set bit, call this X
+
+#if ARM_ARCH >= 5
+ clz r0, r1 @ Get lead 0's count
+ rsbne r0, r0, #31 @ lead 0's -> bit index
+ bx lr @
+#else
+ @ this is the ffs algorithm devised by D.Seal and posted to
+ @ comp.sys.arm on 16 Feb 1994.
+ @
+ @ Output modified to suit Rockbox purposes.
+
+ orrne r1, r1, r1, lsl #4 @ r1 = X * 0x11
+ orrne r1, r1, r1, lsl #6 @ r1 = X * 0x451
+ rsbne r1, r1, r1, lsl #16 @ r1 = X * 0x0450fbaf
+
+ @ now lookup in table indexed on top 6 bits of r1
+ ldrb r0, [ pc, r1, lsr #26 ] @ exploit location of table
+ bx lr @
+
+L_ffs_table:
+ @ 0 1 2 3 4 5 6 7
+ @----------------------------------------------
+ .byte 32, 0, 1, 12, 2, 6, 0, 13 @ 0- 7
+ .byte 3, 0, 7, 0, 0, 0, 0, 14 @ 8-15
+ .byte 10, 4, 0, 0, 8, 0, 0, 25 @ 16-23
+ .byte 0, 0, 0, 0, 0, 21, 27, 15 @ 24-31
+ .byte 31, 11, 5, 0, 0, 0, 0, 0 @ 32-39
+ .byte 9, 0, 0, 24, 0, 0, 20, 26 @ 40-47
+ .byte 30, 0, 0, 0, 0, 23, 0, 19 @ 48-55
+ .byte 29, 0, 22, 18, 28, 17, 16, 0 @ 56-63
+#endif
+ .size find_first_set_bit, .-find_first_set_bit
diff --git a/firmware/asm/ffs.c b/firmware/asm/ffs.c
new file mode 100644
index 0000000000..f68a9cef8c
--- /dev/null
+++ b/firmware/asm/ffs.c
@@ -0,0 +1,56 @@
+/***************************************************************************
+ * __________ __ ___.
+ * Open \______ \ ____ ____ | | _\_ |__ _______ ___
+ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
+ * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
+ * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
+ * \/ \/ \/ \/ \/
+ * $Id$
+ *
+ * Copyright (C) 2008 by Michael Sevakis
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+#include "config.h"
+#include <inttypes.h>
+
+/* find_first_set_bit() - this is a C version of the ffs algorithm devised
+ * by D.Seal and posted to comp.sys.arm on 16 Feb 1994.
+ *
+ * Find the index of the least significant set bit in the word.
+ * return values:
+ * 0 - bit 0 is set
+ * 1 - bit 1 is set
+ * ...
+ * 31 - bit 31 is set
+ * 32 - no bits set
+ */
+
+/* Table shared with assembly code */
+const uint8_t L_ffs_table[64] ICONST_ATTR =
+{
+/* 0 1 2 3 4 5 6 7 */
+/* ----------------------------------------- */
+ 32, 0, 1, 12, 2, 6, 0, 13, /* 0- 7 */
+ 3, 0, 7, 0, 0, 0, 0, 14, /* 8-15 */
+ 10, 4, 0, 0, 8, 0, 0, 25, /* 16-23 */
+ 0, 0, 0, 0, 0, 21, 27, 15, /* 24-31 */
+ 31, 11, 5, 0, 0, 0, 0, 0, /* 32-39 */
+ 9, 0, 0, 24, 0, 0, 20, 26, /* 40-47 */
+ 30, 0, 0, 0, 0, 23, 0, 19, /* 48-55 */
+ 29, 0, 22, 18, 28, 17, 16, 0, /* 56-63 */
+};
+
+#if !defined(CPU_COLDFIRE)
+int find_first_set_bit(uint32_t val)
+{
+ return L_ffs_table[((val & -val)*0x0450fbaf) >> 26];
+}
+#endif
diff --git a/firmware/asm/m68k/ffs.S b/firmware/asm/m68k/ffs.S
new file mode 100644
index 0000000000..2a39ae5bcd
--- /dev/null
+++ b/firmware/asm/m68k/ffs.S
@@ -0,0 +1,78 @@
+/***************************************************************************
+ * __________ __ ___.
+ * Open \______ \ ____ ____ | | _\_ |__ _______ ___
+ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
+ * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
+ * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
+ * \/ \/ \/ \/ \/
+ * $Id$
+ *
+ * Copyright (C) 2008 by Michael Sevakis
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+ #include "config.h"
+
+/****************************************************************************
+ * int find_first_set_bit(uint32_t val);
+ *
+ * Find the index of the least significant set bit in the 32-bit word.
+ *
+ * return values:
+ * 0 - bit 0 is set
+ * 1 - bit 1 is set
+ * ...
+ * 31 - bit 31 is set
+ * 32 - no bits set
+ ****************************************************************************/
+ .text
+ .align 2
+ .global find_first_set_bit
+ .type find_first_set_bit,@function
+find_first_set_bit:
+ | this is a coldfire version of the ffs algorithm devised by D.Seal
+ | and posted to comp.sys.arm on 16 Feb 1994.
+ |
+ | Output modified to suit rockbox purposes.
+
+ | Standard trick to isolate bottom bit in r0 or 0 if r0 = 0 on entry
+ move.l 4(%sp), %d1 | %d1 = %d1 & -%d1
+ lea.l L_ffs_table, %a0 | %a0 = table address
+ move.l %d1, %d0 |
+ neg.l %d1 |
+ and.l %d0, %d1 |
+
+ | now %d1 has at most one set bit, call this X
+
+ move.l #0x0450fbaf, %d0 | %d0 = multiplier
+ mulu.l %d0, %d1 | %d1 = X * 0x0450fbaf
+
+ | now lookup in table indexed on top 6 bits of %d0
+ moveq.l #26, %d0 | %d0 = final shift count
+ lsr.l %d0, %d1 |
+
+ | the top 24 bits of d0 are 0 so just load the value over it
+ move.b (%a0, %d1.l), %d0 |
+ rts |
+
+ .section .irodata
+L_ffs_table:
+ | 0 1 2 3 4 5 6 7
+ |----------------------------------------------
+ .byte 32, 0, 1, 12, 2, 6, 0, 13 | 0- 7
+ .byte 3, 0, 7, 0, 0, 0, 0, 14 | 8-15
+ .byte 10, 4, 0, 0, 8, 0, 0, 25 | 16-23
+ .byte 0, 0, 0, 0, 0, 21, 27, 15 | 24-31
+ .byte 31, 11, 5, 0, 0, 0, 0, 0 | 32-39
+ .byte 9, 0, 0, 24, 0, 0, 20, 26 | 40-47
+ .byte 30, 0, 0, 0, 0, 23, 0, 19 | 48-55
+ .byte 29, 0, 22, 18, 28, 17, 16, 0 | 56-63
+
+ .size find_first_set_bit, .-find_first_set_bit
diff --git a/firmware/asm/mips/ffs.S b/firmware/asm/mips/ffs.S
new file mode 100644
index 0000000000..a2a82a6a32
--- /dev/null
+++ b/firmware/asm/mips/ffs.S
@@ -0,0 +1,59 @@
+/***************************************************************************
+ * __________ __ ___.
+ * Open \______ \ ____ ____ | | _\_ |__ _______ ___
+ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
+ * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
+ * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
+ * \/ \/ \/ \/ \/
+ * $Id$
+ *
+ * Copyright (C) 2009 by Maurus Cuelenaere
+ * based on ffs-arm.S by Michael Sevakis
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#include "config.h"
+#include "mips.h"
+
+/****************************************************************************
+ * int find_first_set_bit(uint32_t val);
+ *
+ * Find the index of the least significant set bit in the 32-bit word.
+ *
+ * return values:
+ * 0 - bit 0 is set
+ * 1 - bit 1 is set
+ * ...
+ * 31 - bit 31 is set
+ * 32 - no bits set
+ ****************************************************************************/
+ .align 2
+ .global find_first_set_bit
+ .type find_first_set_bit, %function
+ .set noreorder
+ .set noat
+
+find_first_set_bit:
+ beqz a0, l # if(a0 == 0) goto l
+ nop #
+ negu t0, a0 # t0 = -a0
+ and t0, a0, t0 # t0 = a0 & t0
+ clz v0, t0 # get lead 0's count
+ li t0, 31 # t0 = 31
+ jr ra #
+ subu v0, t0, v0 # v0 = t0 - v0
+
+l:
+ jr ra #
+ li v0, 32 # v0 = 32
+
+ .set reorder
+ .set at