From nobody Wed Oct 22 15:24:05 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1518674950679749.1042306799905; Wed, 14 Feb 2018 22:09:10 -0800 (PST) Received: from localhost ([::1]:43480 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1emCjF-0006Hp-QV for importer@patchew.org; Thu, 15 Feb 2018 01:09:09 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47714) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1emChd-0005Jy-T2 for qemu-devel@nongnu.org; Thu, 15 Feb 2018 01:07:31 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1emChb-0007cg-61 for qemu-devel@nongnu.org; Thu, 15 Feb 2018 01:07:29 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:40954 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1emChb-0007cP-0R for qemu-devel@nongnu.org; Thu, 15 Feb 2018 01:07:27 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A50267CBB2; Thu, 15 Feb 2018 06:07:26 +0000 (UTC) Received: from amd-seattle-09.khw.lab.eng.bos.redhat.com (amd-seattle-09.khw.lab.eng.bos.redhat.com [10.16.184.112]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5443D2024CA7; Thu, 15 Feb 2018 06:07:26 +0000 (UTC) From: Wei Huang To: qemu-devel@nongnu.org Date: Thu, 15 Feb 2018 01:07:24 -0500 Message-Id: <1518674845-6517-2-git-send-email-wei@redhat.com> In-Reply-To: <1518674845-6517-1-git-send-email-wei@redhat.com> References: <1518674845-6517-1-git-send-email-wei@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Thu, 15 Feb 2018 06:07:26 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Thu, 15 Feb 2018 06:07:26 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'wei@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH V3 1/2] tests/migration: Convert the boot block compilation script into Makefile X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.maydell@linaro.org, drjones@redhat.com, dgilbert@redhat.com, quintela@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" The x86 boot block header currently is generated with a shell script. To better support other CPUs (e.g. aarch64), we convert the script into Makefile. This allows us to 1) support cross-compilation easily; 2) avoid creating a script file for every architecture. Signed-off-by: Wei Huang --- tests/migration/Makefile | 38 ++++++++++++++++++++++++++++= ++++ tests/migration/rebuild-x86-bootblock.sh | 34 ---------------------------- tests/migration/x86-a-b-bootblock.h | 2 +- 3 files changed, 39 insertions(+), 35 deletions(-) create mode 100644 tests/migration/Makefile delete mode 100755 tests/migration/rebuild-x86-bootblock.sh diff --git a/tests/migration/Makefile b/tests/migration/Makefile new file mode 100644 index 0000000..e8e6026 --- /dev/null +++ b/tests/migration/Makefile @@ -0,0 +1,38 @@ +# +# Copyright (c) 2016-2018 Red Hat, Inc. and/or its affiliates +# +# Authors: +# Dave Gilbert +# +# This work is licensed under the terms of the GNU GPL, version 2 or later. +# See the COPYING file in the top-level directory. +# +path :=3D $(subst :, ,$(PATH)) +system :=3D $(shell uname -s | tr "A-Z" "a-z") + +cross-ld =3D $(firstword $(wildcard $(patsubst %,%/$(1)-*$(system)*-ld,$(p= ath)))) +cross-gcc =3D $(firstword $(wildcard $(patsubst %ld,%gcc,$(call cross-ld,$= (1))))) +find-cross-prefix =3D $(subst gcc,,$(notdir $(call cross-gcc,$(1)))) + +x86_64_cross_prefix :=3D $(call find-cross-prefix,x86_64) + +export __note +override define __note +/* This file is automatically generated from + * tests/migration/$<, edit that and then run + * "make $@" inside tests/migration to update, + * and then remember to send both in your patch submission. + */ +endef + +all: x86-a-b-bootblock.h + +x86-a-b-bootblock.h: x86-a-b-bootblock.s + $(x86_64_cross_prefix)as --32 -march=3Di486 $< -o x86.o + $(x86_64_cross_prefix)objcopy -O binary x86.o x86.boot + dd if=3Dx86.boot of=3Dx86.bootsect bs=3D256 count=3D2 skip=3D124 + echo "$$__note" > $@ + xxd -i x86.bootsect | sed -e 's/.*int.*//' >> $@ + +clean: + rm -rf *.bootsect *.boot *.o diff --git a/tests/migration/rebuild-x86-bootblock.sh b/tests/migration/reb= uild-x86-bootblock.sh deleted file mode 100755 index 05ed9ba..0000000 --- a/tests/migration/rebuild-x86-bootblock.sh +++ /dev/null @@ -1,34 +0,0 @@ -#!/bin/sh -# Copyright (c) 2016-2018 Red Hat, Inc. and/or its affiliates -# This work is licensed under the terms of the GNU GPL, version 2 or later. -# See the COPYING file in the top-level directory. -# -# Author: dgilbert@redhat.com - -ASMFILE=3D$PWD/tests/migration/x86-a-b-bootblock.s -HEADER=3D$PWD/tests/migration/x86-a-b-bootblock.h - -if [ ! -e "$ASMFILE" ] -then - echo "Couldn't find $ASMFILE" >&2 - exit 1 -fi - -ASM_WORK_DIR=3D$(mktemp -d --tmpdir X86BB.XXXXXX) -cd "$ASM_WORK_DIR" && -as --32 -march=3Di486 "$ASMFILE" -o x86.o && -objcopy -O binary x86.o x86.boot && -dd if=3Dx86.boot of=3Dx86.bootsect bs=3D256 count=3D2 skip=3D124 && -xxd -i x86.bootsect | -sed -e 's/.*int.*//' > x86.hex && -cat - x86.hex < "$HEADER" -/* This file is automatically generated from - * tests/migration/x86-a-b-bootblock.s, edit that and then run - * tests/migration/rebuild-x86-bootblock.sh to update, - * and then remember to send both in your patch submission. - */ -HERE - -rm x86.hex x86.bootsect x86.boot x86.o -cd .. && rmdir "$ASM_WORK_DIR" - diff --git a/tests/migration/x86-a-b-bootblock.h b/tests/migration/x86-a-b-= bootblock.h index 78a151f..9e8e2e0 100644 --- a/tests/migration/x86-a-b-bootblock.h +++ b/tests/migration/x86-a-b-bootblock.h @@ -1,6 +1,6 @@ /* This file is automatically generated from * tests/migration/x86-a-b-bootblock.s, edit that and then run - * tests/migration/rebuild-x86-bootblock.sh to update, + * "make x86-a-b-bootblock.h" inside tests/migration to update, * and then remember to send both in your patch submission. */ unsigned char x86_bootsect[] =3D { --=20 1.8.3.1 From nobody Wed Oct 22 15:24:05 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (208.118.235.17 [208.118.235.17]) by mx.zohomail.com with SMTPS id 1518675060048809.7115626795644; Wed, 14 Feb 2018 22:11:00 -0800 (PST) Received: from localhost ([::1]:43542 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1emCku-0007pE-3r for importer@patchew.org; Thu, 15 Feb 2018 01:10:52 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47717) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1emChd-0005K0-Ta for qemu-devel@nongnu.org; Thu, 15 Feb 2018 01:07:31 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1emChb-0007dB-Ii for qemu-devel@nongnu.org; Thu, 15 Feb 2018 01:07:29 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:60556 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1emChb-0007cc-D7 for qemu-devel@nongnu.org; Thu, 15 Feb 2018 01:07:27 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0B6984085019; Thu, 15 Feb 2018 06:07:27 +0000 (UTC) Received: from amd-seattle-09.khw.lab.eng.bos.redhat.com (amd-seattle-09.khw.lab.eng.bos.redhat.com [10.16.184.112]) by smtp.corp.redhat.com (Postfix) with ESMTP id B5CC12024CA7; Thu, 15 Feb 2018 06:07:26 +0000 (UTC) From: Wei Huang To: qemu-devel@nongnu.org Date: Thu, 15 Feb 2018 01:07:25 -0500 Message-Id: <1518674845-6517-3-git-send-email-wei@redhat.com> In-Reply-To: <1518674845-6517-1-git-send-email-wei@redhat.com> References: <1518674845-6517-1-git-send-email-wei@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Thu, 15 Feb 2018 06:07:27 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Thu, 15 Feb 2018 06:07:27 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'wei@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH V3 2/2] tests: Add migration test for aarch64 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.maydell@linaro.org, drjones@redhat.com, dgilbert@redhat.com, quintela@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" This patch adds migration test support for aarch64. The test code, which implements the same functionality as x86, is booted as a kernel in qemu. Here are the design choices we make for aarch64: * We choose this -kernel approach because aarch64 QEMU doesn't provide a built-in fw like x86 does. So instead of relying on a boot loader, we use -kernel approach for aarch64. * The serial output is sent to PL011 directly. * The physical memory base for mach-virt machine is 0x40000000. We change the start_address and end_address for aarch64. In addition to providing the binary, this patch also includes the source code and the build script in tests/migration/. So users can change the source and/or re-compile the binary as they wish. Signed-off-by: Wei Huang --- tests/Makefile.include | 1 + tests/migration-test.c | 39 ++++++++++++++++--- tests/migration/Makefile | 12 +++++- tests/migration/aarch64-a-b-kernel.h | 19 +++++++++ tests/migration/aarch64-a-b-kernel.s | 74 ++++++++++++++++++++++++++++++++= ++++ 5 files changed, 137 insertions(+), 8 deletions(-) create mode 100644 tests/migration/aarch64-a-b-kernel.h create mode 100644 tests/migration/aarch64-a-b-kernel.s diff --git a/tests/Makefile.include b/tests/Makefile.include index 278c13a..5b1605a 100644 --- a/tests/Makefile.include +++ b/tests/Makefile.include @@ -372,6 +372,7 @@ check-qtest-arm-y +=3D tests/sdhci-test$(EXESUF) =20 check-qtest-aarch64-y =3D tests/numa-test$(EXESUF) check-qtest-aarch64-y +=3D tests/sdhci-test$(EXESUF) +check-qtest-aarch64-y +=3D tests/migration-test$(EXESUF) =20 check-qtest-microblazeel-y =3D $(check-qtest-microblaze-y) =20 diff --git a/tests/migration-test.c b/tests/migration-test.c index 97fdb19..0b6ab5c 100644 --- a/tests/migration-test.c +++ b/tests/migration-test.c @@ -23,8 +23,8 @@ =20 #define MIN_NVRAM_SIZE 8192 /* from spapr_nvram.c */ =20 -const unsigned start_address =3D 1024 * 1024; -const unsigned end_address =3D 100 * 1024 * 1024; +unsigned start_address =3D 1024 * 1024; +unsigned end_address =3D 100 * 1024 * 1024; bool got_stop; =20 #if defined(__linux__) @@ -81,12 +81,13 @@ static const char *tmpfs; * outputting a 'B' every so often if it's still running. */ #include "tests/migration/x86-a-b-bootblock.h" +#include "tests/migration/aarch64-a-b-kernel.h" =20 -static void init_bootfile_x86(const char *bootpath) +static void init_bootfile(const char *bootpath, void *content) { FILE *bootfile =3D fopen(bootpath, "wb"); =20 - g_assert_cmpint(fwrite(x86_bootsect, 512, 1, bootfile), =3D=3D, 1); + g_assert_cmpint(fwrite(content, 512, 1, bootfile), =3D=3D, 1); fclose(bootfile); } =20 @@ -392,7 +393,7 @@ static void test_migrate_start(QTestState **from, QTest= State **to, got_stop =3D false; =20 if (strcmp(arch, "i386") =3D=3D 0 || strcmp(arch, "x86_64") =3D=3D 0) { - init_bootfile_x86(bootpath); + init_bootfile(bootpath, x86_bootsect); cmd_src =3D g_strdup_printf("-machine accel=3D%s -m 150M" " -name source,debug-threads=3Don" " -serial file:%s/src_serial" @@ -421,6 +422,32 @@ static void test_migrate_start(QTestState **from, QTes= tState **to, " -serial file:%s/dest_serial" " -incoming %s", accel, tmpfs, uri); + } else if (strcmp(arch, "aarch64") =3D=3D 0) { + const char *cpu; + + if (access("/dev/kvm", F_OK)) { + accel =3D "kvm"; + cpu =3D "host"; + } else { + accel =3D "tcg"; + cpu =3D "cortex-a57"; + } + + init_bootfile(bootpath, aarch64_kernel); + cmd_src =3D g_strdup_printf("-machine virt,accel=3D%s -m 150M " + "-name vmsource,debug-threads=3Don -cpu = %s " + "-serial file:%s/src_serial " + "-kernel %s ", + accel, cpu, tmpfs, bootpath); + cmd_dst =3D g_strdup_printf("-machine virt,accel=3D%s -m 150M " + "-name vmdest,debug-threads=3Don -cpu %s= " + "-serial file:%s/dest_serial " + "-kernel %s " + "-incoming %s ", + accel, cpu, tmpfs, bootpath, uri); + /* aarch64 virt machine physical memory starts at 0x40000000 */ + start_address +=3D 0x40000000; + end_address +=3D 0x40000000; } else { g_assert_not_reached(); } @@ -502,7 +529,7 @@ static void test_deprecated(void) { QTestState *from; =20 - from =3D qtest_start(""); + from =3D qtest_start("-machine none"); =20 deprecated_set_downtime(from, 0.12345); deprecated_set_speed(from, "12345"); diff --git a/tests/migration/Makefile b/tests/migration/Makefile index e8e6026..00f854b 100644 --- a/tests/migration/Makefile +++ b/tests/migration/Makefile @@ -15,6 +15,7 @@ cross-gcc =3D $(firstword $(wildcard $(patsubst %ld,%gcc,= $(call cross-ld,$(1))))) find-cross-prefix =3D $(subst gcc,,$(notdir $(call cross-gcc,$(1)))) =20 x86_64_cross_prefix :=3D $(call find-cross-prefix,x86_64) +aarch64_cross_prefix :=3D $(call find-cross-prefix,aarch64) =20 export __note override define __note @@ -25,7 +26,7 @@ override define __note */ endef =20 -all: x86-a-b-bootblock.h +all: x86-a-b-bootblock.h aarch64-a-b-kernel.h =20 x86-a-b-bootblock.h: x86-a-b-bootblock.s $(x86_64_cross_prefix)as --32 -march=3Di486 $< -o x86.o @@ -34,5 +35,12 @@ x86-a-b-bootblock.h: x86-a-b-bootblock.s echo "$$__note" > $@ xxd -i x86.bootsect | sed -e 's/.*int.*//' >> $@ =20 +aarch64-a-b-kernel.h: aarch64-a-b-kernel.s + $(aarch64_cross_prefix)gcc -o aarch64.elf -nostdlib \ + -Wl,--build-id=3Dnone,-Ttext=3D40080000 $< + $(aarch64_cross_prefix)objcopy -O binary aarch64.elf aarch64.kernel + echo "$$__note" > $@ + xxd -i aarch64.kernel | sed -e 's/.*int.*//' >> $@ + clean: - rm -rf *.bootsect *.boot *.o + rm -rf *.bootsect *.boot *.o *.elf *.kernel diff --git a/tests/migration/aarch64-a-b-kernel.h b/tests/migration/aarch64= -a-b-kernel.h new file mode 100644 index 0000000..d294cf8 --- /dev/null +++ b/tests/migration/aarch64-a-b-kernel.h @@ -0,0 +1,19 @@ +/* This file is automatically generated from + * tests/migration/aarch64-a-b-kernel.s, edit that and then run + * "make aarch64-a-b-kernel.h" inside tests/migration to update, + * and then remember to send both in your patch submission. + */ +unsigned char aarch64_kernel[] =3D { + 0x00, 0x10, 0x38, 0xd5, 0x00, 0xf8, 0x7f, 0x92, 0x00, 0x10, 0x18, 0xd5, + 0xdf, 0x3f, 0x03, 0xd5, 0x00, 0x02, 0xa8, 0xd2, 0x01, 0xc8, 0xa8, 0xd2, + 0x23, 0x08, 0x80, 0x52, 0x02, 0x20, 0xa1, 0xd2, 0x43, 0x00, 0x00, 0x39, + 0x03, 0x00, 0x80, 0x52, 0xe4, 0x03, 0x00, 0xaa, 0x83, 0x00, 0x00, 0x39, + 0x84, 0x04, 0x40, 0x91, 0x9f, 0x00, 0x01, 0xeb, 0xad, 0xff, 0xff, 0x54, + 0x05, 0x00, 0x80, 0x52, 0xe4, 0x03, 0x00, 0xaa, 0x24, 0x7e, 0x0b, 0xd5, + 0x83, 0x00, 0x40, 0x39, 0x63, 0x04, 0x00, 0x11, 0x63, 0x1c, 0x00, 0x12, + 0x83, 0x00, 0x00, 0x39, 0x84, 0x04, 0x40, 0x91, 0x9f, 0x00, 0x01, 0xeb, + 0x2b, 0xff, 0xff, 0x54, 0xa5, 0x04, 0x00, 0x11, 0xa5, 0x1c, 0x00, 0x12, + 0xbf, 0x00, 0x00, 0x71, 0x81, 0xfe, 0xff, 0x54, 0x43, 0x08, 0x80, 0x52, + 0x43, 0x00, 0x00, 0x39, 0xf1, 0xff, 0xff, 0x97 +}; + diff --git a/tests/migration/aarch64-a-b-kernel.s b/tests/migration/aarch64= -a-b-kernel.s new file mode 100644 index 0000000..713e7a8 --- /dev/null +++ b/tests/migration/aarch64-a-b-kernel.s @@ -0,0 +1,74 @@ +# +# Copyright (c) 2018 Red Hat, Inc. and/or its affiliates +# +# Author: +# Wei Huang +# +# This work is licensed under the terms of the GNU GPL, version 2 or later. +# See the COPYING file in the top-level directory. + +.set ARM_MACH_VIRT_UART, 0x09000000 +.set ARM_MACH_VIRT_PHYS_BASE, 0x40000000 +.set ARM_MACH_VIRT_A_B_START, (0x40000000 + 1*1024*1024) +.set ARM_MACH_VIRT_A_B_END, (0x40000000 + 100*1024*1024) + +.section .text + + .globl _start + +_start: + /* disable MMU to use phys mem address */ + mrs x0, sctlr_el1 + bic x0, x0, #(1<<0) + msr sctlr_el1, x0 + isb + + /* traverse 1M-100M */ + mov x0, ARM_MACH_VIRT_A_B_START + mov x1, ARM_MACH_VIRT_A_B_END + + /* output char 'A' to PL011 */ + mov w3, 'A' + mov x2, ARM_MACH_VIRT_UART + strb w3, [x2] + + /* clean up memory */ + mov w3, #0 + mov x4, x0 +clean: + strb w3, [x4] + add x4, x4, #(4096) + cmp x4, x1 + ble clean + + /* w5 keeps a counter so we can limit the output speed */ + mov w5, #0 + + /* main body */ +mainloop: + mov x4, x0 + +innerloop: + /* clean cache because el2 might still cache guest data under KVM = */ + dc civac, x4 + + /* increment the first byte of each 4KB page by 1 */ + ldrb w3, [x4] + add w3, w3, #1 + and w3, w3, #(0xff) + strb w3, [x4] + + add x4, x4, #(4096) + cmp x4, x1 + blt innerloop + + add w5, w5, #1 + and w5, w5, #(0xff) + cmp w5, #0 + bne mainloop + + /* output char 'B' to PL011 */ + mov w3, 'B' + strb w3, [x2] + + bl mainloop --=20 1.8.3.1