aboutsummaryrefslogtreecommitdiff
path: root/arch/ia64/lib/memset.S
diff options
context:
space:
mode:
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/ia64/lib/memset.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/ia64/lib/memset.S')
-rw-r--r--arch/ia64/lib/memset.S365
1 files changed, 365 insertions, 0 deletions
diff --git a/arch/ia64/lib/memset.S b/arch/ia64/lib/memset.S
new file mode 100644
index 000000000..07a8b92c6
--- /dev/null
+++ b/arch/ia64/lib/memset.S
@@ -0,0 +1,365 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Optimized version of the standard memset() function.
+
+ Copyright (c) 2002 Hewlett-Packard Co/CERN
+ Sverre Jarp <Sverre.Jarp@cern.ch>
+
+ Return: dest
+
+ Inputs:
+ in0: dest
+ in1: value
+ in2: count
+
+ The algorithm is fairly straightforward: set byte by byte until we
+ we get to a 16B-aligned address, then loop on 128 B chunks using an
+ early store as prefetching, then loop on 32B chucks, then clear remaining
+ words, finally clear remaining bytes.
+ Since a stf.spill f0 can store 16B in one go, we use this instruction
+ to get peak speed when value = 0. */
+
+#include <asm/asmmacro.h>
+#include <asm/export.h>
+#undef ret
+
+#define dest in0
+#define value in1
+#define cnt in2
+
+#define tmp r31
+#define save_lc r30
+#define ptr0 r29
+#define ptr1 r28
+#define ptr2 r27
+#define ptr3 r26
+#define ptr9 r24
+#define loopcnt r23
+#define linecnt r22
+#define bytecnt r21
+
+#define fvalue f6
+
+// This routine uses only scratch predicate registers (p6 - p15)
+#define p_scr p6 // default register for same-cycle branches
+#define p_nz p7
+#define p_zr p8
+#define p_unalgn p9
+#define p_y p11
+#define p_n p12
+#define p_yy p13
+#define p_nn p14
+
+#define MIN1 15
+#define MIN1P1HALF 8
+#define LINE_SIZE 128
+#define LSIZE_SH 7 // shift amount
+#define PREF_AHEAD 8
+
+GLOBAL_ENTRY(memset)
+{ .mmi
+ .prologue
+ alloc tmp = ar.pfs, 3, 0, 0, 0
+ lfetch.nt1 [dest] //
+ .save ar.lc, save_lc
+ mov.i save_lc = ar.lc
+ .body
+} { .mmi
+ mov ret0 = dest // return value
+ cmp.ne p_nz, p_zr = value, r0 // use stf.spill if value is zero
+ cmp.eq p_scr, p0 = cnt, r0
+;; }
+{ .mmi
+ and ptr2 = -(MIN1+1), dest // aligned address
+ and tmp = MIN1, dest // prepare to check for correct alignment
+ tbit.nz p_y, p_n = dest, 0 // Do we have an odd address? (M_B_U)
+} { .mib
+ mov ptr1 = dest
+ mux1 value = value, @brcst // create 8 identical bytes in word
+(p_scr) br.ret.dpnt.many rp // return immediately if count = 0
+;; }
+{ .mib
+ cmp.ne p_unalgn, p0 = tmp, r0 //
+} { .mib
+ sub bytecnt = (MIN1+1), tmp // NB: # of bytes to move is 1 higher than loopcnt
+ cmp.gt p_scr, p0 = 16, cnt // is it a minimalistic task?
+(p_scr) br.cond.dptk.many .move_bytes_unaligned // go move just a few (M_B_U)
+;; }
+{ .mmi
+(p_unalgn) add ptr1 = (MIN1+1), ptr2 // after alignment
+(p_unalgn) add ptr2 = MIN1P1HALF, ptr2 // after alignment
+(p_unalgn) tbit.nz.unc p_y, p_n = bytecnt, 3 // should we do a st8 ?
+;; }
+{ .mib
+(p_y) add cnt = -8, cnt //
+(p_unalgn) tbit.nz.unc p_yy, p_nn = bytecnt, 2 // should we do a st4 ?
+} { .mib
+(p_y) st8 [ptr2] = value,-4 //
+(p_n) add ptr2 = 4, ptr2 //
+;; }
+{ .mib
+(p_yy) add cnt = -4, cnt //
+(p_unalgn) tbit.nz.unc p_y, p_n = bytecnt, 1 // should we do a st2 ?
+} { .mib
+(p_yy) st4 [ptr2] = value,-2 //
+(p_nn) add ptr2 = 2, ptr2 //
+;; }
+{ .mmi
+ mov tmp = LINE_SIZE+1 // for compare
+(p_y) add cnt = -2, cnt //
+(p_unalgn) tbit.nz.unc p_yy, p_nn = bytecnt, 0 // should we do a st1 ?
+} { .mmi
+ setf.sig fvalue=value // transfer value to FLP side
+(p_y) st2 [ptr2] = value,-1 //
+(p_n) add ptr2 = 1, ptr2 //
+;; }
+
+{ .mmi
+(p_yy) st1 [ptr2] = value //
+ cmp.gt p_scr, p0 = tmp, cnt // is it a minimalistic task?
+} { .mbb
+(p_yy) add cnt = -1, cnt //
+(p_scr) br.cond.dpnt.many .fraction_of_line // go move just a few
+;; }
+
+{ .mib
+ nop.m 0
+ shr.u linecnt = cnt, LSIZE_SH
+(p_zr) br.cond.dptk.many .l1b // Jump to use stf.spill
+;; }
+
+ TEXT_ALIGN(32) // --------------------- // L1A: store ahead into cache lines; fill later
+{ .mmi
+ and tmp = -(LINE_SIZE), cnt // compute end of range
+ mov ptr9 = ptr1 // used for prefetching
+ and cnt = (LINE_SIZE-1), cnt // remainder
+} { .mmi
+ mov loopcnt = PREF_AHEAD-1 // default prefetch loop
+ cmp.gt p_scr, p0 = PREF_AHEAD, linecnt // check against actual value
+;; }
+{ .mmi
+(p_scr) add loopcnt = -1, linecnt //
+ add ptr2 = 8, ptr1 // start of stores (beyond prefetch stores)
+ add ptr1 = tmp, ptr1 // first address beyond total range
+;; }
+{ .mmi
+ add tmp = -1, linecnt // next loop count
+ mov.i ar.lc = loopcnt //
+;; }
+.pref_l1a:
+{ .mib
+ stf8 [ptr9] = fvalue, 128 // Do stores one cache line apart
+ nop.i 0
+ br.cloop.dptk.few .pref_l1a
+;; }
+{ .mmi
+ add ptr0 = 16, ptr2 // Two stores in parallel
+ mov.i ar.lc = tmp //
+;; }
+.l1ax:
+ { .mmi
+ stf8 [ptr2] = fvalue, 8
+ stf8 [ptr0] = fvalue, 8
+ ;; }
+ { .mmi
+ stf8 [ptr2] = fvalue, 24
+ stf8 [ptr0] = fvalue, 24
+ ;; }
+ { .mmi
+ stf8 [ptr2] = fvalue, 8
+ stf8 [ptr0] = fvalue, 8
+ ;; }
+ { .mmi
+ stf8 [ptr2] = fvalue, 24
+ stf8 [ptr0] = fvalue, 24
+ ;; }
+ { .mmi
+ stf8 [ptr2] = fvalue, 8
+ stf8 [ptr0] = fvalue, 8
+ ;; }
+ { .mmi
+ stf8 [ptr2] = fvalue, 24
+ stf8 [ptr0] = fvalue, 24
+ ;; }
+ { .mmi
+ stf8 [ptr2] = fvalue, 8
+ stf8 [ptr0] = fvalue, 32
+ cmp.lt p_scr, p0 = ptr9, ptr1 // do we need more prefetching?
+ ;; }
+{ .mmb
+ stf8 [ptr2] = fvalue, 24
+(p_scr) stf8 [ptr9] = fvalue, 128
+ br.cloop.dptk.few .l1ax
+;; }
+{ .mbb
+ cmp.le p_scr, p0 = 8, cnt // just a few bytes left ?
+(p_scr) br.cond.dpnt.many .fraction_of_line // Branch no. 2
+ br.cond.dpnt.many .move_bytes_from_alignment // Branch no. 3
+;; }
+
+ TEXT_ALIGN(32)
+.l1b: // ------------------------------------ // L1B: store ahead into cache lines; fill later
+{ .mmi
+ and tmp = -(LINE_SIZE), cnt // compute end of range
+ mov ptr9 = ptr1 // used for prefetching
+ and cnt = (LINE_SIZE-1), cnt // remainder
+} { .mmi
+ mov loopcnt = PREF_AHEAD-1 // default prefetch loop
+ cmp.gt p_scr, p0 = PREF_AHEAD, linecnt // check against actual value
+;; }
+{ .mmi
+(p_scr) add loopcnt = -1, linecnt
+ add ptr2 = 16, ptr1 // start of stores (beyond prefetch stores)
+ add ptr1 = tmp, ptr1 // first address beyond total range
+;; }
+{ .mmi
+ add tmp = -1, linecnt // next loop count
+ mov.i ar.lc = loopcnt
+;; }
+.pref_l1b:
+{ .mib
+ stf.spill [ptr9] = f0, 128 // Do stores one cache line apart
+ nop.i 0
+ br.cloop.dptk.few .pref_l1b
+;; }
+{ .mmi
+ add ptr0 = 16, ptr2 // Two stores in parallel
+ mov.i ar.lc = tmp
+;; }
+.l1bx:
+ { .mmi
+ stf.spill [ptr2] = f0, 32
+ stf.spill [ptr0] = f0, 32
+ ;; }
+ { .mmi
+ stf.spill [ptr2] = f0, 32
+ stf.spill [ptr0] = f0, 32
+ ;; }
+ { .mmi
+ stf.spill [ptr2] = f0, 32
+ stf.spill [ptr0] = f0, 64
+ cmp.lt p_scr, p0 = ptr9, ptr1 // do we need more prefetching?
+ ;; }
+{ .mmb
+ stf.spill [ptr2] = f0, 32
+(p_scr) stf.spill [ptr9] = f0, 128
+ br.cloop.dptk.few .l1bx
+;; }
+{ .mib
+ cmp.gt p_scr, p0 = 8, cnt // just a few bytes left ?
+(p_scr) br.cond.dpnt.many .move_bytes_from_alignment //
+;; }
+
+.fraction_of_line:
+{ .mib
+ add ptr2 = 16, ptr1
+ shr.u loopcnt = cnt, 5 // loopcnt = cnt / 32
+;; }
+{ .mib
+ cmp.eq p_scr, p0 = loopcnt, r0
+ add loopcnt = -1, loopcnt
+(p_scr) br.cond.dpnt.many .store_words
+;; }
+{ .mib
+ and cnt = 0x1f, cnt // compute the remaining cnt
+ mov.i ar.lc = loopcnt
+;; }
+ TEXT_ALIGN(32)
+.l2: // ------------------------------------ // L2A: store 32B in 2 cycles
+{ .mmb
+ stf8 [ptr1] = fvalue, 8
+ stf8 [ptr2] = fvalue, 8
+;; } { .mmb
+ stf8 [ptr1] = fvalue, 24
+ stf8 [ptr2] = fvalue, 24
+ br.cloop.dptk.many .l2
+;; }
+.store_words:
+{ .mib
+ cmp.gt p_scr, p0 = 8, cnt // just a few bytes left ?
+(p_scr) br.cond.dpnt.many .move_bytes_from_alignment // Branch
+;; }
+
+{ .mmi
+ stf8 [ptr1] = fvalue, 8 // store
+ cmp.le p_y, p_n = 16, cnt
+ add cnt = -8, cnt // subtract
+;; }
+{ .mmi
+(p_y) stf8 [ptr1] = fvalue, 8 // store
+(p_y) cmp.le.unc p_yy, p_nn = 16, cnt
+(p_y) add cnt = -8, cnt // subtract
+;; }
+{ .mmi // store
+(p_yy) stf8 [ptr1] = fvalue, 8
+(p_yy) add cnt = -8, cnt // subtract
+;; }
+
+.move_bytes_from_alignment:
+{ .mib
+ cmp.eq p_scr, p0 = cnt, r0
+ tbit.nz.unc p_y, p0 = cnt, 2 // should we terminate with a st4 ?
+(p_scr) br.cond.dpnt.few .restore_and_exit
+;; }
+{ .mib
+(p_y) st4 [ptr1] = value,4
+ tbit.nz.unc p_yy, p0 = cnt, 1 // should we terminate with a st2 ?
+;; }
+{ .mib
+(p_yy) st2 [ptr1] = value,2
+ tbit.nz.unc p_y, p0 = cnt, 0 // should we terminate with a st1 ?
+;; }
+
+{ .mib
+(p_y) st1 [ptr1] = value
+;; }
+.restore_and_exit:
+{ .mib
+ nop.m 0
+ mov.i ar.lc = save_lc
+ br.ret.sptk.many rp
+;; }
+
+.move_bytes_unaligned:
+{ .mmi
+ .pred.rel "mutex",p_y, p_n
+ .pred.rel "mutex",p_yy, p_nn
+(p_n) cmp.le p_yy, p_nn = 4, cnt
+(p_y) cmp.le p_yy, p_nn = 5, cnt
+(p_n) add ptr2 = 2, ptr1
+} { .mmi
+(p_y) add ptr2 = 3, ptr1
+(p_y) st1 [ptr1] = value, 1 // fill 1 (odd-aligned) byte [15, 14 (or less) left]
+(p_y) add cnt = -1, cnt
+;; }
+{ .mmi
+(p_yy) cmp.le.unc p_y, p0 = 8, cnt
+ add ptr3 = ptr1, cnt // prepare last store
+ mov.i ar.lc = save_lc
+} { .mmi
+(p_yy) st2 [ptr1] = value, 4 // fill 2 (aligned) bytes
+(p_yy) st2 [ptr2] = value, 4 // fill 2 (aligned) bytes [11, 10 (o less) left]
+(p_yy) add cnt = -4, cnt
+;; }
+{ .mmi
+(p_y) cmp.le.unc p_yy, p0 = 8, cnt
+ add ptr3 = -1, ptr3 // last store
+ tbit.nz p_scr, p0 = cnt, 1 // will there be a st2 at the end ?
+} { .mmi
+(p_y) st2 [ptr1] = value, 4 // fill 2 (aligned) bytes
+(p_y) st2 [ptr2] = value, 4 // fill 2 (aligned) bytes [7, 6 (or less) left]
+(p_y) add cnt = -4, cnt
+;; }
+{ .mmi
+(p_yy) st2 [ptr1] = value, 4 // fill 2 (aligned) bytes
+(p_yy) st2 [ptr2] = value, 4 // fill 2 (aligned) bytes [3, 2 (or less) left]
+ tbit.nz p_y, p0 = cnt, 0 // will there be a st1 at the end ?
+} { .mmi
+(p_yy) add cnt = -4, cnt
+;; }
+{ .mmb
+(p_scr) st2 [ptr1] = value // fill 2 (aligned) bytes
+(p_y) st1 [ptr3] = value // fill last byte (using ptr3)
+ br.ret.sptk.many rp
+}
+END(memset)
+EXPORT_SYMBOL(memset)