summaryrefslogtreecommitdiff
path: root/lib_avr32
diff options
context:
space:
mode:
authorWolfgang Denk <wd@pollux.denx.de>2006-10-24 14:21:16 +0200
committerWolfgang Denk <wd@pollux.denx.de>2006-10-24 14:21:16 +0200
commit7b64fef33c66be648826c0ff9758298ef13d0604 (patch)
treeea8a3685319987b5d135c2f48e9bc1eee4720640 /lib_avr32
parent2da2d9a4766063b9848f3a35ad6025499cf87265 (diff)
downloadu-boot-imx-7b64fef33c66be648826c0ff9758298ef13d0604.zip
u-boot-imx-7b64fef33c66be648826c0ff9758298ef13d0604.tar.gz
u-boot-imx-7b64fef33c66be648826c0ff9758298ef13d0604.tar.bz2
Add AVR32 architecture support
Patch by Haavard Skinnemoen, 6 Sep 2006 16:23:02 +0200 This patch adds common infrastructure code for the Atmel AVR32 architecture. See doc/README.AVR32 for details. Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Diffstat (limited to 'lib_avr32')
-rw-r--r--lib_avr32/Makefile47
-rw-r--r--lib_avr32/avr32_linux.c315
-rw-r--r--lib_avr32/board.c175
-rw-r--r--lib_avr32/div64.c54
-rw-r--r--lib_avr32/interrupts.c39
-rw-r--r--lib_avr32/memset.S81
6 files changed, 711 insertions, 0 deletions
diff --git a/lib_avr32/Makefile b/lib_avr32/Makefile
new file mode 100644
index 0000000..5b6300b
--- /dev/null
+++ b/lib_avr32/Makefile
@@ -0,0 +1,47 @@
+#
+# (C) Copyright 2002-2006
+# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+#
+# (C) Copyright 2004-2006 Atmel Corporation
+#
+# See file CREDITS for list of people who contributed to this
+# project.
+#
+# 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 program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+# MA 02111-1307 USA
+#
+
+include $(TOPDIR)/config.mk
+
+LIB = $(obj)lib$(ARCH).a
+
+SOBJS = memset.o
+
+COBJS = board.o interrupts.o avr32_linux.o div64.o
+
+SRCS := $(SOBJS:.o=.S) $(COBJS:.o=.c)
+OBJS := $(addprefix $(obj),$(SOBJS) $(COBJS))
+
+$(LIB): $(obj).depend $(OBJS)
+ $(AR) crv $@ $(OBJS)
+
+#########################################################################
+
+# defines $(obj).depend target
+include $(SRCTREE)/rules.mk
+
+sinclude $(obj).depend
+
+#########################################################################
diff --git a/lib_avr32/avr32_linux.c b/lib_avr32/avr32_linux.c
new file mode 100644
index 0000000..d128dfb
--- /dev/null
+++ b/lib_avr32/avr32_linux.c
@@ -0,0 +1,315 @@
+/*
+ * Copyright (C) 2004-2006 Atmel Corporation
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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 program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+#include <common.h>
+#include <command.h>
+#include <image.h>
+#include <zlib.h>
+#include <asm/byteorder.h>
+#include <asm/addrspace.h>
+#include <asm/io.h>
+#include <asm/setup.h>
+#include <asm/arch/platform.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+extern int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
+
+/* CPU-specific hook to allow flushing of caches, etc. */
+extern void prepare_to_boot(void);
+
+#ifdef CONFIG_SHOW_BOOT_PROGRESS
+# include <status_led.h>
+# define SHOW_BOOT_PROGRESS(arg) show_boot_progress(arg)
+#else
+# define SHOW_BOOT_PROGRESS(arg)
+#endif
+
+extern image_header_t header; /* from cmd_bootm.c */
+
+static struct tag *setup_start_tag(struct tag *params)
+{
+ params->hdr.tag = ATAG_CORE;
+ params->hdr.size = tag_size(tag_core);
+
+ params->u.core.flags = 0;
+ params->u.core.pagesize = 4096;
+ params->u.core.rootdev = 0;
+
+ return tag_next(params);
+}
+
+static struct tag *setup_memory_tags(struct tag *params)
+{
+ bd_t *bd = gd->bd;
+ int i;
+
+ for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++) {
+ params->hdr.tag = ATAG_MEM;
+ params->hdr.size = tag_size(tag_mem_range);
+
+ params->u.mem_range.addr = bd->bi_dram[i].start;
+ params->u.mem_range.size = bd->bi_dram[i].size;
+
+ params = tag_next(params);
+ }
+
+ return params;
+}
+
+static struct tag *setup_commandline_tag(struct tag *params, char *cmdline)
+{
+ if (!cmdline)
+ return params;
+
+ /* eat leading white space */
+ while (*cmdline == ' ') cmdline++;
+
+ /*
+ * Don't include tags for empty command lines; let the kernel
+ * use its default command line.
+ */
+ if (*cmdline == '\0')
+ return params;
+
+ params->hdr.tag = ATAG_CMDLINE;
+ params->hdr.size =
+ (sizeof (struct tag_header) + strlen(cmdline) + 1 + 3) >> 2;
+ strcpy(params->u.cmdline.cmdline, cmdline);
+
+ return tag_next(params);
+}
+
+static struct tag *setup_ramdisk_tag(struct tag *params,
+ unsigned long rd_start,
+ unsigned long rd_end)
+{
+ if (rd_start == rd_end)
+ return params;
+
+ params->hdr.tag = ATAG_RDIMG;
+ params->hdr.size = tag_size(tag_mem_range);
+
+ params->u.mem_range.addr = rd_start;
+ params->u.mem_range.size = rd_end - rd_start;
+
+ return tag_next(params);
+}
+
+static struct tag *setup_clock_tags(struct tag *params)
+{
+ params->hdr.tag = ATAG_CLOCK;
+ params->hdr.size = tag_size(tag_clock);
+ params->u.clock.clock_id = ACLOCK_BOOTCPU;
+ params->u.clock.clock_flags = 0;
+ params->u.clock.clock_hz = gd->cpu_hz;
+
+#ifdef CONFIG_AT32AP7000
+ /*
+ * New kernels don't need this, but we should be backwards
+ * compatible for a while...
+ */
+ params = tag_next(params);
+
+ params->hdr.tag = ATAG_CLOCK;
+ params->hdr.size = tag_size(tag_clock);
+ params->u.clock.clock_id = ACLOCK_HSB;
+ params->u.clock.clock_flags = 0;
+ params->u.clock.clock_hz = pm_get_clock_freq(CLOCK_HSB);
+#endif
+
+ return tag_next(params);
+}
+
+static struct tag *setup_ethernet_tag(struct tag *params,
+ char *addr, int index)
+{
+ char *s, *e;
+ int i;
+
+ params->hdr.tag = ATAG_ETHERNET;
+ params->hdr.size = tag_size(tag_ethernet);
+
+ params->u.ethernet.mac_index = index;
+ params->u.ethernet.mii_phy_addr = gd->bd->bi_phy_id[index];
+
+ s = addr;
+ for (i = 0; i < 6; i++) {
+ params->u.ethernet.hw_address[i] = simple_strtoul(s, &e, 16);
+ s = e + 1;
+ }
+
+ return tag_next(params);
+}
+
+static struct tag *setup_ethernet_tags(struct tag *params)
+{
+ char name[16] = "ethaddr";
+ char *addr;
+ int i = 0;
+
+ do {
+ addr = getenv(name);
+ if (addr)
+ params = setup_ethernet_tag(params, addr, i);
+ sprintf(name, "eth%daddr", ++i);
+ } while (i < 4);
+
+ return params;
+}
+
+static void setup_end_tag(struct tag *params)
+{
+ params->hdr.tag = ATAG_NONE;
+ params->hdr.size = 0;
+}
+
+void do_bootm_linux(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[],
+ unsigned long addr, unsigned long *len_ptr, int verify)
+{
+ unsigned long data, len = 0;
+ unsigned long initrd_start, initrd_end;
+ unsigned long image_start, image_end;
+ unsigned long checksum;
+ void (*theKernel)(int magic, void *tagtable);
+ image_header_t *hdr;
+ struct tag *params, *params_start;
+ char *commandline = getenv("bootargs");
+
+ hdr = (image_header_t *)addr;
+ image_start = addr;
+ image_end = addr + hdr->ih_size;
+
+ theKernel = (void *)ntohl(hdr->ih_ep);
+
+ /*
+ * Check if there is an initrd image
+ */
+ if (argc >= 3) {
+ SHOW_BOOT_PROGRESS(9);
+
+ addr = simple_strtoul(argv[2], NULL, 16);
+
+ printf("## Loading RAMDISK image at %08lx ...\n", addr);
+
+ memcpy(&header, (char *)addr, sizeof(header));
+ hdr = &header;
+
+ if (ntohl(hdr->ih_magic) != IH_MAGIC) {
+ puts("Bad Magic Number\n");
+ SHOW_BOOT_PROGRESS(-10);
+ do_reset(cmdtp, flag, argc, argv);
+ }
+
+ data = (unsigned long)hdr;
+ len = sizeof(*hdr);
+ checksum = ntohl(hdr->ih_hcrc);
+ hdr->ih_hcrc = 0;
+
+ if (crc32(0, (unsigned char *)data, len) != checksum) {
+ puts("Bad Header Checksum\n");
+ SHOW_BOOT_PROGRESS(-11);
+ do_reset(cmdtp, flag, argc, argv);
+ }
+
+ SHOW_BOOT_PROGRESS(10);
+
+ print_image_hdr(hdr);
+
+ data = addr + sizeof(header);
+ len = ntohl(hdr->ih_size);
+
+ if (verify) {
+ unsigned long csum = 0;
+
+ puts(" Verifying Checksum ... ");
+ csum = crc32(0, (unsigned char *)data, len);
+ if (csum != ntohl(hdr->ih_dcrc)) {
+ puts("Bad Data CRC\n");
+ SHOW_BOOT_PROGRESS(-12);
+ do_reset(cmdtp, flag, argc, argv);
+ }
+ puts("OK\n");
+ }
+
+ SHOW_BOOT_PROGRESS(11);
+
+ if ((hdr->ih_os != IH_OS_LINUX) ||
+ (hdr->ih_arch != IH_CPU_AVR32) ||
+ (hdr->ih_type != IH_TYPE_RAMDISK)) {
+ puts("Not a Linux/AVR32 RAMDISK image\n");
+ SHOW_BOOT_PROGRESS(-13);
+ do_reset(cmdtp, flag, argc, argv);
+ }
+ } else if ((hdr->ih_type == IH_TYPE_MULTI) && (len_ptr[1])) {
+ ulong tail = ntohl (len_ptr[0]) % 4;
+ int i;
+
+ SHOW_BOOT_PROGRESS (13);
+
+ /* skip kernel length and terminator */
+ data = (ulong) (&len_ptr[2]);
+ /* skip any additional image length fields */
+ for (i = 1; len_ptr[i]; ++i)
+ data += 4;
+ /* add kernel length, and align */
+ data += ntohl (len_ptr[0]);
+ if (tail) {
+ data += 4 - tail;
+ }
+
+ len = ntohl (len_ptr[1]);
+ } else {
+ /* no initrd image */
+ SHOW_BOOT_PROGRESS(14);
+ len = data = 0;
+ }
+
+ if (data) {
+ initrd_start = data;
+ initrd_end = initrd_start + len;
+ } else {
+ initrd_start = 0;
+ initrd_end = 0;
+ }
+
+ SHOW_BOOT_PROGRESS(15);
+
+ params = params_start = (struct tag *)gd->bd->bi_boot_params;
+ params = setup_start_tag(params);
+ params = setup_memory_tags(params);
+ if (initrd_start) {
+ params = setup_ramdisk_tag(params,
+ PHYSADDR(initrd_start),
+ PHYSADDR(initrd_end));
+ }
+ params = setup_commandline_tag(params, commandline);
+ params = setup_clock_tags(params);
+ params = setup_ethernet_tags(params);
+ setup_end_tag(params);
+
+ printf("\nStarting kernel at %p (params at %p)...\n\n",
+ theKernel, params_start);
+
+ prepare_to_boot();
+
+ theKernel(ATAG_MAGIC, params_start);
+}
diff --git a/lib_avr32/board.c b/lib_avr32/board.c
new file mode 100644
index 0000000..02c106b
--- /dev/null
+++ b/lib_avr32/board.c
@@ -0,0 +1,175 @@
+/*
+ * Copyright (C) 2004-2006 Atmel Corporation
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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 program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+#include <common.h>
+#include <command.h>
+#include <malloc.h>
+#include <devices.h>
+#include <version.h>
+#include <net.h>
+
+#include <asm/initcalls.h>
+#include <asm/sections.h>
+
+#ifndef CONFIG_IDENT_STRING
+#define CONFIG_IDENT_STRING ""
+#endif
+
+DECLARE_GLOBAL_DATA_PTR;
+
+const char version_string[] =
+ U_BOOT_VERSION " (" __DATE__ " - " __TIME__ ") " CONFIG_IDENT_STRING;
+
+unsigned long monitor_flash_len;
+
+/*
+ * Begin and end of memory area for malloc(), and current "brk"
+ */
+static unsigned long mem_malloc_start = 0;
+static unsigned long mem_malloc_end = 0;
+static unsigned long mem_malloc_brk = 0;
+
+/* The malloc area is wherever the board wants it to be */
+static void mem_malloc_init(void)
+{
+ mem_malloc_start = CFG_MALLOC_START;
+ mem_malloc_end = CFG_MALLOC_END;
+ mem_malloc_brk = mem_malloc_start;
+
+ printf("malloc: Using memory from 0x%08lx to 0x%08lx\n",
+ mem_malloc_start, mem_malloc_end);
+
+ memset ((void *)mem_malloc_start, 0,
+ mem_malloc_end - mem_malloc_start);
+}
+
+void *sbrk(ptrdiff_t increment)
+{
+ unsigned long old = mem_malloc_brk;
+ unsigned long new = old + increment;
+
+ if ((new < mem_malloc_start) || (new > mem_malloc_end))
+ return NULL;
+
+ mem_malloc_brk = new;
+ return ((void *)old);
+}
+
+static int init_baudrate(void)
+{
+ char tmp[64];
+ int i;
+
+ i = getenv_r("baudrate", tmp, sizeof(tmp));
+ if (i > 0) {
+ gd->baudrate = simple_strtoul(tmp, NULL, 10);
+ } else {
+ gd->baudrate = CONFIG_BAUDRATE;
+ }
+ return 0;
+}
+
+
+static int display_banner (void)
+{
+ printf ("\n\n%s\n\n", version_string);
+ printf ("U-Boot code: %p -> %p data: %p -> %p\n",
+ _text, _etext, _data, _end);
+ return 0;
+}
+
+void hang(void)
+{
+ for (;;) ;
+}
+
+static int display_dram_config (void)
+{
+ int i;
+
+ puts ("DRAM Configuration:\n");
+
+ for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++) {
+ printf ("Bank #%d: %08lx ", i, gd->bd->bi_dram[i].start);
+ print_size (gd->bd->bi_dram[i].size, "\n");
+ }
+
+ return 0;
+}
+
+static void display_flash_config (void)
+{
+ puts ("Flash: ");
+ print_size(gd->bd->bi_flashsize, " ");
+ printf("at address 0x%08lx\n", gd->bd->bi_flashstart);
+}
+
+void start_u_boot (void)
+{
+ gd_t gd_data;
+
+ /* Initialize the global data pointer */
+ memset(&gd_data, 0, sizeof(gd_data));
+ gd = &gd_data;
+
+ monitor_flash_len = _edata - _text;
+
+ /* Perform initialization sequence */
+ cpu_init();
+ timer_init();
+ env_init();
+ init_baudrate();
+ serial_init();
+ console_init_f();
+ display_banner();
+
+ board_init_memories();
+ mem_malloc_init();
+
+ gd->bd = malloc(sizeof(bd_t));
+ memset(gd->bd, 0, sizeof(bd_t));
+ gd->bd->bi_baudrate = gd->baudrate;
+ gd->bd->bi_dram[0].start = CFG_SDRAM_BASE;
+ gd->bd->bi_dram[0].size = gd->sdram_size;
+
+ board_init_info();
+ flash_init();
+
+ if (gd->bd->bi_flashsize)
+ display_flash_config();
+ if (gd->bd->bi_dram[0].size)
+ display_dram_config();
+
+ gd->bd->bi_boot_params = malloc(CFG_BOOTPARAMS_LEN);
+ if (!gd->bd->bi_boot_params)
+ puts("WARNING: Cannot allocate space for boot parameters\n");
+
+ /* initialize environment */
+ env_relocate();
+
+ devices_init();
+ jumptable_init();
+ console_init_r();
+
+ for (;;) {
+ main_loop();
+ }
+}
diff --git a/lib_avr32/div64.c b/lib_avr32/div64.c
new file mode 100644
index 0000000..99726e3
--- /dev/null
+++ b/lib_avr32/div64.c
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2003 Bernardo Innocenti <bernie@develer.com>
+ *
+ * Based on former do_div() implementation from asm-parisc/div64.h:
+ * Copyright (C) 1999 Hewlett-Packard Co
+ * Copyright (C) 1999 David Mosberger-Tang <davidm@hpl.hp.com>
+ *
+ *
+ * Generic C version of 64bit/32bit division and modulo, with
+ * 64bit result and 32bit remainder.
+ *
+ * The fast case for (n>>32 == 0) is handled inline by do_div().
+ *
+ * Code generated for this function might be very inefficient
+ * for some CPUs. __div64_32() can be overridden by linking arch-specific
+ * assembly versions such as arch/ppc/lib/div64.S and arch/sh/lib/div64.S.
+ */
+
+#include <linux/types.h>
+
+#include <asm/div64.h>
+
+uint32_t __div64_32(uint64_t *n, uint32_t base)
+{
+ uint64_t rem = *n;
+ uint64_t b = base;
+ uint64_t res, d = 1;
+ uint32_t high = rem >> 32;
+
+ /* Reduce the thing a bit first */
+ res = 0;
+ if (high >= base) {
+ high /= base;
+ res = (uint64_t) high << 32;
+ rem -= (uint64_t) (high*base) << 32;
+ }
+
+ while ((int64_t)b > 0 && b < rem) {
+ b = b+b;
+ d = d+d;
+ }
+
+ do {
+ if (rem >= b) {
+ rem -= b;
+ res += d;
+ }
+ b >>= 1;
+ d >>= 1;
+ } while (d);
+
+ *n = res;
+ return rem;
+}
diff --git a/lib_avr32/interrupts.c b/lib_avr32/interrupts.c
new file mode 100644
index 0000000..ce538f3
--- /dev/null
+++ b/lib_avr32/interrupts.c
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2006 Atmel Corporation
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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 program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+#include <common.h>
+
+#include <asm/sysreg.h>
+
+void enable_interrupts(void)
+{
+ asm volatile("csrf %0" : : "n"(SYSREG_GM_OFFSET));
+}
+
+int disable_interrupts(void)
+{
+ unsigned long sr;
+
+ sr = sysreg_read(SR);
+ asm volatile("ssrf %0" : : "n"(SYSREG_GM_OFFSET));
+
+ return SYSREG_BFEXT(GM, sr);
+}
diff --git a/lib_avr32/memset.S b/lib_avr32/memset.S
new file mode 100644
index 0000000..dc3b09b
--- /dev/null
+++ b/lib_avr32/memset.S
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2004-2006 Atmel Corporation
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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 program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+ /*
+ * r12: void *b
+ * r11: int c
+ * r10: size_t len
+ *
+ * Returns b in r12
+ */
+ .text
+
+ .global memset
+ .type memset, @function
+ .align 2
+memset:
+ mov r9, r12
+ mov r8, r12
+ or r11, r11, r11 << 8
+ andl r9, 3, COH
+ brne 1f
+
+2: or r11, r11, r11 << 16
+ sub r10, 4
+ brlt 5f
+
+ /* Let's do some real work */
+4: st.w r8++, r11
+ sub r10, 4
+ brge 4b
+
+ /*
+ * When we get here, we've got less than 4 bytes to set. r10
+ * might be negative.
+ */
+5: sub r10, -4
+ reteq r12
+
+ /* Fastpath ends here, exactly 32 bytes from memset */
+
+ /* Handle unaligned count or pointer */
+ bld r10, 1
+ brcc 6f
+ st.b r8++, r11
+ st.b r8++, r11
+ bld r10, 0
+ retcc r12
+6: st.b r8++, r11
+ mov pc, lr
+
+ /* Handle unaligned pointer */
+1: sub r10, 4
+ brlt 5b
+ add r10, r9
+ lsl r9, 1
+ add pc, r9
+ st.b r8++, r11
+ st.b r8++, r11
+ st.b r8++, r11
+ rjmp 2b
+
+ .size memset, . - memset