[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 4
The attached patches provides part 4 of an architecture implementation for the
Tensilica Xtensa CPU series.
Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/xtensa/lib/memcopy.S b/arch/xtensa/lib/memcopy.S
new file mode 100644
index 0000000..e8f6d7e
--- /dev/null
+++ b/arch/xtensa/lib/memcopy.S
@@ -0,0 +1,315 @@
+/*
+ * arch/xtensa/lib/hal/memcopy.S -- Core HAL library functions
+ * xthal_memcpy and xthal_bcopy
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2002 - 2005 Tensilica Inc.
+ */
+
+#include <xtensa/coreasm.h>
+
+ .macro src_b r, w0, w1
+#ifdef __XTENSA_EB__
+ src \r, \w0, \w1
+#else
+ src \r, \w1, \w0
+#endif
+ .endm
+
+ .macro ssa8 r
+#ifdef __XTENSA_EB__
+ ssa8b \r
+#else
+ ssa8l \r
+#endif
+ .endm
+
+
+/*
+ * void *memcpy(void *dst, const void *src, size_t len);
+ * void *memmove(void *dst, const void *src, size_t len);
+ * void *bcopy(const void *src, void *dst, size_t len);
+ *
+ * This function is intended to do the same thing as the standard
+ * library function memcpy() (or bcopy()) for most cases.
+ * However, where the source and/or destination references
+ * an instruction RAM or ROM or a data RAM or ROM, that
+ * source and/or destination will always be accessed with
+ * 32-bit load and store instructions (as required for these
+ * types of devices).
+ *
+ * !!!!!!! XTFIXME:
+ * !!!!!!! Handling of IRAM/IROM has not yet
+ * !!!!!!! been implemented.
+ *
+ * The bcopy version is provided here to avoid the overhead
+ * of an extra call, for callers that require this convention.
+ *
+ * The (general case) algorithm is as follows:
+ * If destination is unaligned, align it by conditionally
+ * copying 1 and 2 bytes.
+ * If source is aligned,
+ * do 16 bytes with a loop, and then finish up with
+ * 8, 4, 2, and 1 byte copies conditional on the length;
+ * else (if source is unaligned),
+ * do the same, but use SRC to align the source data.
+ * This code tries to use fall-through branches for the common
+ * case of aligned source and destination and multiple
+ * of 4 (or 8) length.
+ *
+ * Register use:
+ * a0/ return address
+ * a1/ stack pointer
+ * a2/ return value
+ * a3/ src
+ * a4/ length
+ * a5/ dst
+ * a6/ tmp
+ * a7/ tmp
+ * a8/ tmp
+ * a9/ tmp
+ * a10/ tmp
+ * a11/ tmp
+ */
+
+ .text
+ .align 4
+ .global bcopy
+ .type bcopy,@function
+bcopy:
+ entry sp, 16 # minimal stack frame
+ # a2=src, a3=dst, a4=len
+ mov a5, a3 # copy dst so that a2 is return value
+ mov a3, a2
+ mov a2, a5
+ j .Lcommon # go to common code for memcpy+bcopy
+
+
+/*
+ * Byte by byte copy
+ */
+ .align 4
+ .byte 0 # 1 mod 4 alignment for LOOPNEZ
+ # (0 mod 4 alignment for LBEG)
+.Lbytecopy:
+#if XCHAL_HAVE_LOOPS
+ loopnez a4, .Lbytecopydone
+#else /* !XCHAL_HAVE_LOOPS */
+ beqz a4, .Lbytecopydone
+ add a7, a3, a4 # a7 = end address for source
+#endif /* !XCHAL_HAVE_LOOPS */
+.Lnextbyte:
+ l8ui a6, a3, 0
+ addi a3, a3, 1
+ s8i a6, a5, 0
+ addi a5, a5, 1
+#if !XCHAL_HAVE_LOOPS
+ blt a3, a7, .Lnextbyte
+#endif /* !XCHAL_HAVE_LOOPS */
+.Lbytecopydone:
+ retw
+
+/*
+ * Destination is unaligned
+ */
+
+ .align 4
+.Ldst1mod2: # dst is only byte aligned
+ _bltui a4, 7, .Lbytecopy # do short copies byte by byte
+
+ # copy 1 byte
+ l8ui a6, a3, 0
+ addi a3, a3, 1
+ addi a4, a4, -1
+ s8i a6, a5, 0
+ addi a5, a5, 1
+ _bbci.l a5, 1, .Ldstaligned # if dst is now aligned, then
+ # return to main algorithm
+.Ldst2mod4: # dst 16-bit aligned
+ # copy 2 bytes
+ _bltui a4, 6, .Lbytecopy # do short copies byte by byte
+ l8ui a6, a3, 0
+ l8ui a7, a3, 1
+ addi a3, a3, 2
+ addi a4, a4, -2
+ s8i a6, a5, 0
+ s8i a7, a5, 1
+ addi a5, a5, 2
+ j .Ldstaligned # dst is now aligned, return to main algorithm
+
+ .align 4
+ .global memcpy
+ .type memcpy,@function
+memcpy:
+ .global memmove
+ .type memmove,@function
+memmove:
+
+ entry sp, 16 # minimal stack frame
+ # a2/ dst, a3/ src, a4/ len
+ mov a5, a2 # copy dst so that a2 is return value
+.Lcommon:
+ _bbsi.l a2, 0, .Ldst1mod2 # if dst is 1 mod 2
+ _bbsi.l a2, 1, .Ldst2mod4 # if dst is 2 mod 4
+.Ldstaligned: # return here from .Ldst?mod? once dst is aligned
+ srli a7, a4, 4 # number of loop iterations with 16B
+ # per iteration
+ movi a8, 3 # if source is not aligned,
+ _bany a3, a8, .Lsrcunaligned # then use shifting copy
+ /*
+ * Destination and source are word-aligned, use word copy.
+ */
+ # copy 16 bytes per iteration for word-aligned dst and word-aligned src
+#if XCHAL_HAVE_LOOPS
+ loopnez a7, .Loop1done
+#else /* !XCHAL_HAVE_LOOPS */
+ beqz a7, .Loop1done
+ slli a8, a7, 4
+ add a8, a8, a3 # a8 = end of last 16B source chunk
+#endif /* !XCHAL_HAVE_LOOPS */
+.Loop1:
+ l32i a6, a3, 0
+ l32i a7, a3, 4
+ s32i a6, a5, 0
+ l32i a6, a3, 8
+ s32i a7, a5, 4
+ l32i a7, a3, 12
+ s32i a6, a5, 8
+ addi a3, a3, 16
+ s32i a7, a5, 12
+ addi a5, a5, 16
+#if !XCHAL_HAVE_LOOPS
+ blt a3, a8, .Loop1
+#endif /* !XCHAL_HAVE_LOOPS */
+.Loop1done:
+ bbci.l a4, 3, .L2
+ # copy 8 bytes
+ l32i a6, a3, 0
+ l32i a7, a3, 4
+ addi a3, a3, 8
+ s32i a6, a5, 0
+ s32i a7, a5, 4
+ addi a5, a5, 8
+.L2:
+ bbsi.l a4, 2, .L3
+ bbsi.l a4, 1, .L4
+ bbsi.l a4, 0, .L5
+ retw
+.L3:
+ # copy 4 bytes
+ l32i a6, a3, 0
+ addi a3, a3, 4
+ s32i a6, a5, 0
+ addi a5, a5, 4
+ bbsi.l a4, 1, .L4
+ bbsi.l a4, 0, .L5
+ retw
+.L4:
+ # copy 2 bytes
+ l16ui a6, a3, 0
+ addi a3, a3, 2
+ s16i a6, a5, 0
+ addi a5, a5, 2
+ bbsi.l a4, 0, .L5
+ retw
+.L5:
+ # copy 1 byte
+ l8ui a6, a3, 0
+ s8i a6, a5, 0
+ retw
+
+/*
+ * Destination is aligned, Source is unaligned
+ */
+
+ .align 4
+.Lsrcunaligned:
+ _beqz a4, .Ldone # avoid loading anything for zero-length copies
+ # copy 16 bytes per iteration for word-aligned dst and unaligned src
+ ssa8 a3 # set shift amount from byte offset
+#define SIM_CHECKS_ALIGNMENT 1 /* set to 1 when running on ISS (simulator) with the
+ lint or ferret client, or 0 to save a few cycles */
+#if XCHAL_UNALIGNED_LOAD_EXCEPTION || SIM_CHECKS_ALIGNMENT
+ and a11, a3, a8 # save unalignment offset for below
+ sub a3, a3, a11 # align a3
+#endif
+ l32i a6, a3, 0 # load first word
+#if XCHAL_HAVE_LOOPS
+ loopnez a7, .Loop2done
+#else /* !XCHAL_HAVE_LOOPS */
+ beqz a7, .Loop2done
+ slli a10, a7, 4
+ add a10, a10, a3 # a10 = end of last 16B source chunk
+#endif /* !XCHAL_HAVE_LOOPS */
+.Loop2:
+ l32i a7, a3, 4
+ l32i a8, a3, 8
+ src_b a6, a6, a7
+ s32i a6, a5, 0
+ l32i a9, a3, 12
+ src_b a7, a7, a8
+ s32i a7, a5, 4
+ l32i a6, a3, 16
+ src_b a8, a8, a9
+ s32i a8, a5, 8
+ addi a3, a3, 16
+ src_b a9, a9, a6
+ s32i a9, a5, 12
+ addi a5, a5, 16
+#if !XCHAL_HAVE_LOOPS
+ blt a3, a10, .Loop2
+#endif /* !XCHAL_HAVE_LOOPS */
+.Loop2done:
+ bbci.l a4, 3, .L12
+ # copy 8 bytes
+ l32i a7, a3, 4
+ l32i a8, a3, 8
+ src_b a6, a6, a7
+ s32i a6, a5, 0
+ addi a3, a3, 8
+ src_b a7, a7, a8
+ s32i a7, a5, 4
+ addi a5, a5, 8
+ mov a6, a8
+.L12:
+ bbci.l a4, 2, .L13
+ # copy 4 bytes
+ l32i a7, a3, 4
+ addi a3, a3, 4
+ src_b a6, a6, a7
+ s32i a6, a5, 0
+ addi a5, a5, 4
+ mov a6, a7
+.L13:
+#if XCHAL_UNALIGNED_LOAD_EXCEPTION || SIM_CHECKS_ALIGNMENT
+ add a3, a3, a11 # readjust a3 with correct misalignment
+#endif
+ bbsi.l a4, 1, .L14
+ bbsi.l a4, 0, .L15
+.Ldone: retw
+.L14:
+ # copy 2 bytes
+ l8ui a6, a3, 0
+ l8ui a7, a3, 1
+ addi a3, a3, 2
+ s8i a6, a5, 0
+ s8i a7, a5, 1
+ addi a5, a5, 2
+ bbsi.l a4, 0, .L15
+ retw
+.L15:
+ # copy 1 byte
+ l8ui a6, a3, 0
+ s8i a6, a5, 0
+ retw
+
+/*
+ * Local Variables:
+ * mode:fundamental
+ * comment-start: "# "
+ * comment-start-skip: "# *"
+ * End:
+ */