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authorLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
committerLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
commit5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch)
treecc5c2d0a898769fd59549594fedb3ee6f84e59a0 /arch/xtensa/lib/memcopy.S
downloadlinux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz
linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.zip
Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted
Pull networking updates from Jakub Kicinski: "Core: - Add dedicated kmem_cache for typical/small skb->head, avoid having to access struct page at kfree time, and improve memory use. - Introduce sysctl to set default RPS configuration for new netdevs. - Define Netlink protocol specification format which can be used to describe messages used by each family and auto-generate parsers. Add tools for generating kernel data structures and uAPI headers. - Expose all net/core sysctls inside netns. - Remove 4s sleep in netpoll if carrier is instantly detected on boot. - Add configurable limit of MDB entries per port, and port-vlan. - Continue populating drop reasons throughout the stack. - Retire a handful of legacy Qdiscs and classifiers. Protocols: - Support IPv4 big TCP (TSO frames larger than 64kB). - Add IP_LOCAL_PORT_RANGE socket option, to control local port range on socket by socket basis. - Track and report in procfs number of MPTCP sockets used. - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path manager. - IPv6: don't check net.ipv6.route.max_size and rely on garbage collection to free memory (similarly to IPv4). - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986). - ICMP: add per-rate limit counters. - Add support for user scanning requests in ieee802154. - Remove static WEP support. - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate reporting. - WiFi 7 EHT channel puncturing support (client & AP). BPF: - Add a rbtree data structure following the "next-gen data structure" precedent set by recently added linked list, that is, by using kfunc + kptr instead of adding a new BPF map type. - Expose XDP hints via kfuncs with initial support for RX hash and timestamp metadata. - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better support decap on GRE tunnel devices not operating in collect metadata. - Improve x86 JIT's codegen for PROBE_MEM runtime error checks. - Remove the need for trace_printk_lock for bpf_trace_printk and bpf_trace_vprintk helpers. - Extend libbpf's bpf_tracing.h support for tracing arguments of kprobes/uprobes and syscall as a special case. - Significantly reduce the search time for module symbols by livepatch and BPF. - Enable cpumasks to be used as kptrs, which is useful for tracing programs tracking which tasks end up running on which CPUs in different time intervals. - Add support for BPF trampoline on s390x and riscv64. - Add capability to export the XDP features supported by the NIC. - Add __bpf_kfunc tag for marking kernel functions as kfuncs. - Add cgroup.memory=nobpf kernel parameter option to disable BPF memory accounting for container environments. Netfilter: - Remove the CLUSTERIP target. It has been marked as obsolete for years, and we still have WARN splats wrt races of the out-of-band /proc interface installed by this target. - Add 'destroy' commands to nf_tables. They are identical to the existing 'delete' commands, but do not return an error if the referenced object (set, chain, rule...) did not exist. Driver API: - Improve cpumask_local_spread() locality to help NICs set the right IRQ affinity on AMD platforms. - Separate C22 and C45 MDIO bus transactions more clearly. - Introduce new DCB table to control DSCP rewrite on egress. - Support configuration of Physical Layer Collision Avoidance (PLCA) Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of shared medium Ethernet. - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing preemption of low priority frames by high priority frames. - Add support for controlling MACSec offload using netlink SET. - Rework devlink instance refcounts to allow registration and de-registration under the instance lock. Split the code into multiple files, drop some of the unnecessarily granular locks and factor out common parts of netlink operation handling. - Add TX frame aggregation parameters (for USB drivers). - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning messages with notifications for debug. - Allow offloading of UDP NEW connections via act_ct. - Add support for per action HW stats in TC. - Support hardware miss to TC action (continue processing in SW from a specific point in the action chain). - Warn if old Wireless Extension user space interface is used with modern cfg80211/mac80211 drivers. Do not support Wireless Extensions for Wi-Fi 7 devices at all. Everyone should switch to using nl80211 interface instead. - Improve the CAN bit timing configuration. Use extack to return error messages directly to user space, update the SJW handling, including the definition of a new default value that will benefit CAN-FD controllers, by increasing their oscillator tolerance. New hardware / drivers: - Ethernet: - nVidia BlueField-3 support (control traffic driver) - Ethernet support for imx93 SoCs - Motorcomm yt8531 gigabit Ethernet PHY - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA) - Microchip LAN8841 PHY (incl. cable diagnostics and PTP) - Amlogic gxl MDIO mux - WiFi: - RealTek RTL8188EU (rtl8xxxu) - Qualcomm Wi-Fi 7 devices (ath12k) - CAN: - Renesas R-Car V4H Drivers: - Bluetooth: - Set Per Platform Antenna Gain (PPAG) for Intel controllers. - Ethernet NICs: - Intel (1G, igc): - support TSN / Qbv / packet scheduling features of i226 model - Intel (100G, ice): - use GNSS subsystem instead of TTY - multi-buffer XDP support - extend support for GPIO pins to E823 devices - nVidia/Mellanox: - update the shared buffer configuration on PFC commands - implement PTP adjphase function for HW offset control - TC support for Geneve and GRE with VF tunnel offload - more efficient crypto key management method - multi-port eswitch support - Netronome/Corigine: - add DCB IEEE support - support IPsec offloading for NFP3800 - Freescale/NXP (enetc): - support XDP_REDIRECT for XDP non-linear buffers - improve reconfig, avoid link flap and waiting for idle - support MAC Merge layer - Other NICs: - sfc/ef100: add basic devlink support for ef100 - ionic: rx_push mode operation (writing descriptors via MMIO) - bnxt: use the auxiliary bus abstraction for RDMA - r8169: disable ASPM and reset bus in case of tx timeout - cpsw: support QSGMII mode for J721e CPSW9G - cpts: support pulse-per-second output - ngbe: add an mdio bus driver - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing - r8152: handle devices with FW with NCM support - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation - virtio-net: support multi buffer XDP - virtio/vsock: replace virtio_vsock_pkt with sk_buff - tsnep: XDP support - Ethernet high-speed switches: - nVidia/Mellanox (mlxsw): - add support for latency TLV (in FW control messages) - Microchip (sparx5): - separate explicit and implicit traffic forwarding rules, make the implicit rules always active - add support for egress DSCP rewrite - IS0 VCAP support (Ingress Classification) - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS etc.) - ES2 VCAP support (Egress Access Control) - support for Per-Stream Filtering and Policing (802.1Q, 8.6.5.1) - Ethernet embedded switches: - Marvell (mv88e6xxx): - add MAB (port auth) offload support - enable PTP receive for mv88e6390 - NXP (ocelot): - support MAC Merge layer - support for the the vsc7512 internal copper phys - Microchip: - lan9303: convert to PHYLINK - lan966x: support TC flower filter statistics - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x - lan937x: support Credit Based Shaper configuration - ksz9477: support Energy Efficient Ethernet - other: - qca8k: convert to regmap read/write API, use bulk operations - rswitch: Improve TX timestamp accuracy - Intel WiFi (iwlwifi): - EHT (Wi-Fi 7) rate reporting - STEP equalizer support: transfer some STEP (connection to radio on platforms with integrated wifi) related parameters from the BIOS to the firmware. - Qualcomm 802.11ax WiFi (ath11k): - IPQ5018 support - Fine Timing Measurement (FTM) responder role support - channel 177 support - MediaTek WiFi (mt76): - per-PHY LED support - mt7996: EHT (Wi-Fi 7) support - Wireless Ethernet Dispatch (WED) reset support - switch to using page pool allocator - RealTek WiFi (rtw89): - support new version of Bluetooth co-existance - Mobile: - rmnet: support TX aggregation" * tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits) page_pool: add a comment explaining the fragment counter usage net: ethtool: fix __ethtool_dev_mm_supported() implementation ethtool: pse-pd: Fix double word in comments xsk: add linux/vmalloc.h to xsk.c sefltests: netdevsim: wait for devlink instance after netns removal selftest: fib_tests: Always cleanup before exit net/mlx5e: Align IPsec ASO result memory to be as required by hardware net/mlx5e: TC, Set CT miss to the specific ct action instance net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG net/mlx5: Refactor tc miss handling to a single function net/mlx5: Kconfig: Make tc offload depend on tc skb extension net/sched: flower: Support hardware miss to tc action net/sched: flower: Move filter handle initialization earlier net/sched: cls_api: Support hardware miss to tc action net/sched: Rename user cookie and act cookie sfc: fix builds without CONFIG_RTC_LIB sfc: clean up some inconsistent indentings net/mlx4_en: Introduce flexible array to silence overflow warning net: lan966x: Fix possible deadlock inside PTP net/ulp: Remove redundant ->clone() test in inet_clone_ulp(). ...
Diffstat (limited to 'arch/xtensa/lib/memcopy.S')
-rw-r--r--arch/xtensa/lib/memcopy.S553
1 files changed, 553 insertions, 0 deletions
diff --git a/arch/xtensa/lib/memcopy.S b/arch/xtensa/lib/memcopy.S
new file mode 100644
index 000000000..b20d206bc
--- /dev/null
+++ b/arch/xtensa/lib/memcopy.S
@@ -0,0 +1,553 @@
+/*
+ * 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 - 2012 Tensilica Inc.
+ */
+
+#include <linux/linkage.h>
+#include <asm/asmmacro.h>
+#include <asm/core.h>
+
+/*
+ * void *memcpy(void *dst, const void *src, size_t len);
+ *
+ * This function is intended to do the same thing as the standard
+ * library function memcpy() 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 (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
+
+/*
+ * 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
+ bne a3, a7, .Lnextbyte # continue loop if $a3:src != $a7:src_end
+#endif /* !XCHAL_HAVE_LOOPS */
+.Lbytecopydone:
+ abi_ret_default
+
+/*
+ * 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
+
+ENTRY(__memcpy)
+WEAK(memcpy)
+
+ abi_entry_default
+ # 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
+ bne a3, a8, .Loop1 # continue loop if a3:src != a8:src_end
+#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
+ abi_ret_default
+.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
+ abi_ret_default
+.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
+ abi_ret_default
+.L5:
+ # copy 1 byte
+ l8ui a6, a3, 0
+ s8i a6, a5, 0
+ abi_ret_default
+
+/*
+ * 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
+
+/* set to 1 when running on ISS (simulator) with the
+ lint or ferret client, or 0 to save a few cycles */
+#define SIM_CHECKS_ALIGNMENT 1
+#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
+ bne a3, a10, .Loop2 # continue loop if a3:src != a10:src_end
+#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: abi_ret_default
+.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
+ abi_ret_default
+.L15:
+ # copy 1 byte
+ l8ui a6, a3, 0
+ s8i a6, a5, 0
+ abi_ret_default
+
+ENDPROC(__memcpy)
+
+/*
+ * void bcopy(const void *src, void *dest, size_t n);
+ */
+
+ENTRY(bcopy)
+
+ abi_entry_default
+ # a2=src, a3=dst, a4=len
+ mov a5, a3
+ mov a3, a2
+ mov a2, a5
+ j .Lmovecommon # go to common code for memmove+bcopy
+
+ENDPROC(bcopy)
+
+/*
+ * void *memmove(void *dst, const void *src, size_t len);
+ *
+ * This function is intended to do the same thing as the standard
+ * library function memmove() 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 (general case) algorithm is as follows:
+ * If end of source doesn't overlap destination then use memcpy.
+ * Otherwise do memcpy backwards.
+ *
+ * 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
+ */
+
+/*
+ * Byte by byte copy
+ */
+ .align 4
+ .byte 0 # 1 mod 4 alignment for LOOPNEZ
+ # (0 mod 4 alignment for LBEG)
+.Lbackbytecopy:
+#if XCHAL_HAVE_LOOPS
+ loopnez a4, .Lbackbytecopydone
+#else /* !XCHAL_HAVE_LOOPS */
+ beqz a4, .Lbackbytecopydone
+ sub a7, a3, a4 # a7 = start address for source
+#endif /* !XCHAL_HAVE_LOOPS */
+.Lbacknextbyte:
+ addi a3, a3, -1
+ l8ui a6, a3, 0
+ addi a5, a5, -1
+ s8i a6, a5, 0
+#if !XCHAL_HAVE_LOOPS
+ bne a3, a7, .Lbacknextbyte # continue loop if
+ # $a3:src != $a7:src_start
+#endif /* !XCHAL_HAVE_LOOPS */
+.Lbackbytecopydone:
+ abi_ret_default
+
+/*
+ * Destination is unaligned
+ */
+
+ .align 4
+.Lbackdst1mod2: # dst is only byte aligned
+ _bltui a4, 7, .Lbackbytecopy # do short copies byte by byte
+
+ # copy 1 byte
+ addi a3, a3, -1
+ l8ui a6, a3, 0
+ addi a5, a5, -1
+ s8i a6, a5, 0
+ addi a4, a4, -1
+ _bbci.l a5, 1, .Lbackdstaligned # if dst is now aligned, then
+ # return to main algorithm
+.Lbackdst2mod4: # dst 16-bit aligned
+ # copy 2 bytes
+ _bltui a4, 6, .Lbackbytecopy # do short copies byte by byte
+ addi a3, a3, -2
+ l8ui a6, a3, 0
+ l8ui a7, a3, 1
+ addi a5, a5, -2
+ s8i a6, a5, 0
+ s8i a7, a5, 1
+ addi a4, a4, -2
+ j .Lbackdstaligned # dst is now aligned,
+ # return to main algorithm
+
+ENTRY(__memmove)
+WEAK(memmove)
+
+ abi_entry_default
+ # a2/ dst, a3/ src, a4/ len
+ mov a5, a2 # copy dst so that a2 is return value
+.Lmovecommon:
+ sub a6, a5, a3
+ bgeu a6, a4, .Lcommon
+
+ add a5, a5, a4
+ add a3, a3, a4
+
+ _bbsi.l a5, 0, .Lbackdst1mod2 # if dst is 1 mod 2
+ _bbsi.l a5, 1, .Lbackdst2mod4 # if dst is 2 mod 4
+.Lbackdstaligned: # return here from .Lbackdst?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, .Lbacksrcunaligned # 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, .LbackLoop1done
+#else /* !XCHAL_HAVE_LOOPS */
+ beqz a7, .LbackLoop1done
+ slli a8, a7, 4
+ sub a8, a3, a8 # a8 = start of first 16B source chunk
+#endif /* !XCHAL_HAVE_LOOPS */
+.LbackLoop1:
+ addi a3, a3, -16
+ l32i a7, a3, 12
+ l32i a6, a3, 8
+ addi a5, a5, -16
+ s32i a7, a5, 12
+ l32i a7, a3, 4
+ s32i a6, a5, 8
+ l32i a6, a3, 0
+ s32i a7, a5, 4
+ s32i a6, a5, 0
+#if !XCHAL_HAVE_LOOPS
+ bne a3, a8, .LbackLoop1 # continue loop if a3:src != a8:src_start
+#endif /* !XCHAL_HAVE_LOOPS */
+.LbackLoop1done:
+ bbci.l a4, 3, .Lback2
+ # copy 8 bytes
+ addi a3, a3, -8
+ l32i a6, a3, 0
+ l32i a7, a3, 4
+ addi a5, a5, -8
+ s32i a6, a5, 0
+ s32i a7, a5, 4
+.Lback2:
+ bbsi.l a4, 2, .Lback3
+ bbsi.l a4, 1, .Lback4
+ bbsi.l a4, 0, .Lback5
+ abi_ret_default
+.Lback3:
+ # copy 4 bytes
+ addi a3, a3, -4
+ l32i a6, a3, 0
+ addi a5, a5, -4
+ s32i a6, a5, 0
+ bbsi.l a4, 1, .Lback4
+ bbsi.l a4, 0, .Lback5
+ abi_ret_default
+.Lback4:
+ # copy 2 bytes
+ addi a3, a3, -2
+ l16ui a6, a3, 0
+ addi a5, a5, -2
+ s16i a6, a5, 0
+ bbsi.l a4, 0, .Lback5
+ abi_ret_default
+.Lback5:
+ # copy 1 byte
+ addi a3, a3, -1
+ l8ui a6, a3, 0
+ addi a5, a5, -1
+ s8i a6, a5, 0
+ abi_ret_default
+
+/*
+ * Destination is aligned, Source is unaligned
+ */
+
+ .align 4
+.Lbacksrcunaligned:
+ _beqz a4, .Lbackdone # 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 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, .LbackLoop2done
+#else /* !XCHAL_HAVE_LOOPS */
+ beqz a7, .LbackLoop2done
+ slli a10, a7, 4
+ sub a10, a3, a10 # a10 = start of first 16B source chunk
+#endif /* !XCHAL_HAVE_LOOPS */
+.LbackLoop2:
+ addi a3, a3, -16
+ l32i a7, a3, 12
+ l32i a8, a3, 8
+ addi a5, a5, -16
+ __src_b a6, a7, a6
+ s32i a6, a5, 12
+ l32i a9, a3, 4
+ __src_b a7, a8, a7
+ s32i a7, a5, 8
+ l32i a6, a3, 0
+ __src_b a8, a9, a8
+ s32i a8, a5, 4
+ __src_b a9, a6, a9
+ s32i a9, a5, 0
+#if !XCHAL_HAVE_LOOPS
+ bne a3, a10, .LbackLoop2 # continue loop if a3:src != a10:src_start
+#endif /* !XCHAL_HAVE_LOOPS */
+.LbackLoop2done:
+ bbci.l a4, 3, .Lback12
+ # copy 8 bytes
+ addi a3, a3, -8
+ l32i a7, a3, 4
+ l32i a8, a3, 0
+ addi a5, a5, -8
+ __src_b a6, a7, a6
+ s32i a6, a5, 4
+ __src_b a7, a8, a7
+ s32i a7, a5, 0
+ mov a6, a8
+.Lback12:
+ bbci.l a4, 2, .Lback13
+ # copy 4 bytes
+ addi a3, a3, -4
+ l32i a7, a3, 0
+ addi a5, a5, -4
+ __src_b a6, a7, a6
+ s32i a6, a5, 0
+ mov a6, a7
+.Lback13:
+#if XCHAL_UNALIGNED_LOAD_EXCEPTION || SIM_CHECKS_ALIGNMENT
+ add a3, a3, a11 # readjust a3 with correct misalignment
+#endif
+ bbsi.l a4, 1, .Lback14
+ bbsi.l a4, 0, .Lback15
+.Lbackdone:
+ abi_ret_default
+.Lback14:
+ # copy 2 bytes
+ addi a3, a3, -2
+ l8ui a6, a3, 0
+ l8ui a7, a3, 1
+ addi a5, a5, -2
+ s8i a6, a5, 0
+ s8i a7, a5, 1
+ bbsi.l a4, 0, .Lback15
+ abi_ret_default
+.Lback15:
+ # copy 1 byte
+ addi a3, a3, -1
+ addi a5, a5, -1
+ l8ui a6, a3, 0
+ s8i a6, a5, 0
+ abi_ret_default
+
+ENDPROC(__memmove)