From 37149aa84dcd2b1254b3cbc114a2c35510931ac5 Mon Sep 17 00:00:00 2001
From: Jan Nieuwenhuizen <janneke@gnu.org>
Date: Thu, 7 Mar 2019 21:24:50 +0100
Subject: [PATCH] porting: arm scaffold WIP

---
 lib/arm-mes-gcc/exit-42.S             | 46 +++++++++++++++++++++
 lib/arm-mes-gcc/hello-mes.S           | 58 ++++++++++++++++++++++++++
 lib/arm-mes/elf-0footer.hex2          | 27 ------------
 lib/arm-mes/elf32-0exit-42.hex2       | 34 +++++++++++++++
 lib/arm-mes/elf32-0header.hex2        | 47 ++++++++++++---------
 lib/arm-mes/elf32-0hello-mes.hex2     | 50 +++++++++++++++++++++++
 lib/arm-mes/elf32-body-exit-42.hex2   | 57 +++++++++++++-------------
 lib/arm-mes/elf32-body-hello-mes.hex2 | 59 +++++++++++++++++++++++++++
 lib/arm-mes/elf32-header.hex2         | 44 ++++++++++++--------
 9 files changed, 328 insertions(+), 94 deletions(-)
 create mode 100644 lib/arm-mes-gcc/exit-42.S
 create mode 100644 lib/arm-mes-gcc/hello-mes.S
 delete mode 100644 lib/arm-mes/elf-0footer.hex2
 create mode 100644 lib/arm-mes/elf32-0exit-42.hex2
 create mode 100644 lib/arm-mes/elf32-0hello-mes.hex2
 create mode 100644 lib/arm-mes/elf32-body-hello-mes.hex2

diff --git a/lib/arm-mes-gcc/exit-42.S b/lib/arm-mes-gcc/exit-42.S
new file mode 100644
index 00000000..afe33713
--- /dev/null
+++ b/lib/arm-mes-gcc/exit-42.S
@@ -0,0 +1,46 @@
+/*
+ * GNU Mes --- Maxwell Equations of Software
+ * Copyright © 2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ *
+ * This file is part of GNU Mes.
+ *
+ * GNU Mes 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 3 of the License, or (at
+ * your option) any later version.
+ *
+ * GNU Mes 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 GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** Commentary: */
+
+/* Using gdb, esp. GUD in GNU Emacs is recommended
+M-x gdb-display-disassembly-buffer
+M-x gdb-display-io-buffer
+set disassemble-next-line on
+break _start
+run
+info registers
+si
+p/x $r0
+RET
+...
+*/
+
+/** Code: */
+
+SYS_exit = 1 			/* Linux syscall: exit.  */
+	.globl _start		/* Magic linker symbol: --entry-address.  */
+
+	.text			/* Program text. */
+_start:
+	mov	r7,$SYS_exit	/* System call function: exit, in r7.  */
+	mov	r0,$42		/* First parameter: exit status, in r0. */
+	swi	0		/* Call system.  */
+	wfi 			/* Should not be reached.  */
diff --git a/lib/arm-mes-gcc/hello-mes.S b/lib/arm-mes-gcc/hello-mes.S
new file mode 100644
index 00000000..a86928f4
--- /dev/null
+++ b/lib/arm-mes-gcc/hello-mes.S
@@ -0,0 +1,58 @@
+/*
+ * GNU Mes --- Maxwell Equations of Software
+ * Copyright © 2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ *
+ * This file is part of GNU Mes.
+ *
+ * GNU Mes 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 3 of the License, or (at
+ * your option) any later version.
+ *
+ * GNU Mes 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 GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** Commentary: */
+
+/* Using gdb, esp. GUD in GNU Emacs is recommended
+M-x gdb-display-disassembly-buffer
+M-x gdb-display-io-buffer
+set disassemble-next-line on
+break _start
+run
+info registers
+si
+p/x $r0
+RET
+...
+*/
+
+/** Code: */
+
+SYS_exit 	= 1		/* Linux syscalls.  */
+SYS_write 	= 4
+stdout		= 1		/* File discriptor */
+	.globl _start		/* Magic linker symbol: --entry-address.  */
+
+	.text			/* Program text. */
+_start:
+	mov	r7, $SYS_write	/* System call function: write, in r7.  */
+	mov	r0, $stdout	/* 1st parameter: file descriptor, in r0. */
+	add	r1, pc, $(hello - here - 4) /* 2nd parameter: address, in r1. */
+here:
+	mov	r2, $(bye-hello)	/* 3rd parameter: byte count r2. */
+	swi     0		/* Call system.  */
+
+	mov	r7,$SYS_exit	/* System call function: exit, in r7.  */
+	mov	r0,$0		/* 1st parameter: exit status, in r0. */
+	swi	0		/* Call system.  */
+	wfi 			/* Should not be reached.  */
+
+hello:	.ascii	"Hello, GNU Mes!\n"
+bye:
diff --git a/lib/arm-mes/elf-0footer.hex2 b/lib/arm-mes/elf-0footer.hex2
deleted file mode 100644
index ef856bc8..00000000
--- a/lib/arm-mes/elf-0footer.hex2
+++ /dev/null
@@ -1,27 +0,0 @@
-### Copyright (C) 2017 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
-### Copyright (C) 2019 Danny Milosavljevic <dannym@scratchpost.org>
-### This file is part of stage0.
-###
-### stage0 is free software: you an redistribute it and/or modify
-### it under the terms of the GNU General Public License as published by
-### the Free Software Foundation, either version 3 of the License, or
-### (at your option) any later version.
-###
-### stage0 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 stage0.  If not, see <http://www.gnu.org/licenses/>.
-
-### stage0's hex2 format for arm
-###    !<label>          1 byte relative
-###    $<label>          2 byte address
-###    @<label>          2 byte relative
-###    &<label>          4 byte address
-###    %<label>          4 byte relative
-###    local_<label>     function-local
-###    string_<index>    string #<index>
-
-:ELF_end
diff --git a/lib/arm-mes/elf32-0exit-42.hex2 b/lib/arm-mes/elf32-0exit-42.hex2
new file mode 100644
index 00000000..9f078871
--- /dev/null
+++ b/lib/arm-mes/elf32-0exit-42.hex2
@@ -0,0 +1,34 @@
+### GNU Mes --- Maxwell Equations of Software
+### Copyright (C) 2017,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+### Copyright (C) 2019 Danny Milosavljevic <dannym@scratchpost.org>
+###
+### This file is part of GNU Mes.
+###
+### GNU Mes 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 3 of the License, or (at
+### your option) any later version.
+###
+### GNU Mes 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 GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
+
+### Commentary:
+
+# elf32-exit-42.hex2: `exit 42' for arm-linux written in hex2 assembly,
+# for usage with elf32-0header.hex2.  This produces a 112-byte binary
+# (70 hex).  Inspiration was taken from GNU Gcc output of exit-42.S.
+
+### Code:
+
+# @60
+:ELF_text
+01 70 a0 e3                    # mov    r7,$0x1
+2a 00 a0 e3                    # mov    r0,$0x2a
+00 00 00 ef                    # swi    0
+03 f0 20 e3                    # wfi
+:ELF_end
diff --git a/lib/arm-mes/elf32-0header.hex2 b/lib/arm-mes/elf32-0header.hex2
index 689f82d3..7e0f59f9 100644
--- a/lib/arm-mes/elf32-0header.hex2
+++ b/lib/arm-mes/elf32-0header.hex2
@@ -1,31 +1,39 @@
 ### Copyright (C) 2016 Jeremiah Orians
-### Copyright (C) 2017 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+### Copyright (C) 2017,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
 ### Copyright (C) 2019 Danny Milosavljevic <dannym@scratchpost.org>
-### This file is part of stage0.
 ###
-### stage0 is free software: you an redistribute it and/or modify
-### it under the terms of the GNU General Public License as published by
-### the Free Software Foundation, either version 3 of the License, or
-### (at your option) any later version.
+### This file is part of GNU Mes.
 ###
-### stage0 is distributed in the hope that it will be useful,
-### but WITHOUT ANY WARRANTY; without even the implied warranty of
+### GNU Mes 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 3 of the License, or (at
+### your option) any later version.
+###
+### GNU Mes 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 stage0.  If not, see <http://www.gnu.org/licenses/>.
+### along with GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
 
-### stage0's hex2 format for arm
-###    !<label>          1 byte relative
-###    $<label>          2 byte address
-###    @<label>          2 byte relative
-###    &<label>          4 byte address
-###    %<label>          4 byte relative
-###    local_<label>     function-local
-###    string_<index>    string #<index>
+### Commentary:
 
-### elf32-header-exit-42.hex2: 32 bit elf header in hex2 for `exit 42'
+# elf32-0header.hex2: Simplest 32 bit elf header in hex2.  Only a text
+# segment, no data segment, no symbol tables.
+
+# stage0's hex2 format for arm
+#    !<label>          1 byte relative
+#    $<label>          2 byte address
+#    @<label>          2 byte relative
+#    ~<label>          3 byte relative
+#    &<label>          4 byte address
+#    %<label>          4 byte relative
+#    local_<label>     function-local
+#    string_<index>    string #<index>
+#    ^                 align
+
+### Code:
 
 :ELF_base
 7F 45 4C 46                    # e_ident[EI_MAG0-3] ELF's magic number
@@ -39,8 +47,6 @@
 
 00 00 00 00 00 00 00           # e_ident[EI_PAD]
 
-# Row 2 in od:
-
 02 00                          # e_type Indicating Executable
 28 00                          # e_machine Indicating 32bit arm
 01 00 00 00                    # e_version Indicating original elf
@@ -78,4 +84,5 @@
 07 00 00 00                    # ph_flags: PF-X|PF-W|PF-R = 7
 01 00 00 00                    # ph_align
 
+# @60
 :ELF_text
diff --git a/lib/arm-mes/elf32-0hello-mes.hex2 b/lib/arm-mes/elf32-0hello-mes.hex2
new file mode 100644
index 00000000..7c4788fe
--- /dev/null
+++ b/lib/arm-mes/elf32-0hello-mes.hex2
@@ -0,0 +1,50 @@
+### GNU Mes --- Maxwell Equations of Software
+### Copyright © 2017,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+### Copyright © 2019 Danny Milosavljevic <dannym@scratchpost.org>
+###
+### This file is part of GNU Mes.
+###
+### GNU Mes 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 3 of the License, or (at
+### your option) any later version.
+###
+### GNU Mes 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 GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
+
+### Commentary:
+
+# elf32-0hello-mes.hex2: `Hello, GNU Mes!' for arm-linux written in
+# hex2 assembly, for usage with elf32-0header.hex2.  This produces a
+# 160-byte binary (a0 hex).  Inspiration was taken from GNU Gcc output
+# of hello-mes.S.
+
+### Code:
+
+# @60
+:ELF_text
+                               # print <hello>
+04 70 a0 e3                    # mov    r7, #4
+01 00 a0 e3                    # mov    r0, #1
+!hello 10 8f e2                # add    r1, pc, $(hello - pc)
+!bye>hello 20 a0 e3            # mov    r2, $(bye-hello)
+00 00 00 ef                    # swi    0
+
+                               # exit 0
+01 70 a0 e3                    # mov    r7, #1
+00 00 a0 e3                    # mov    r0, #0
+00 00 00 ef                    # swi    0
+03 f0 20 e3                    # wfi
+
+# @90
+:ELF_data
+:hello
+48 65 6c 6c 6f 2c 20 47        # Hello, G
+4e 55 20 4d 65 73 21 0a        # NU Mes!\n
+:bye
+:ELF_end
diff --git a/lib/arm-mes/elf32-body-exit-42.hex2 b/lib/arm-mes/elf32-body-exit-42.hex2
index f407e298..f974b167 100644
--- a/lib/arm-mes/elf32-body-exit-42.hex2
+++ b/lib/arm-mes/elf32-body-exit-42.hex2
@@ -1,49 +1,48 @@
-### Copyright (C) 2017 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+### Copyright (C) 2017,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
 ### Copyright (C) 2019 Danny Milosavljevic <dannym@scratchpost.org>
-### This file is part of stage0.
 ###
-### stage0 is free software: you an redistribute it and/or modify
-### it under the terms of the GNU General Public License as published by
-### the Free Software Foundation, either version 3 of the License, or
-### (at your option) any later version.
+### This file is part of GNU Mes.
 ###
-### stage0 is distributed in the hope that it will be useful,
-### but WITHOUT ANY WARRANTY; without even the implied warranty of
+### GNU Mes 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 3 of the License, or (at
+### your option) any later version.
+###
+### GNU Mes 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 stage0.  If not, see <http://www.gnu.org/licenses/>.
+### along with GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
 
-### stage0's hex2 format for arm
-###    !<label>          1 byte relative
-###    $<label>          2 byte address
-###    @<label>          2 byte relative
-###    &<label>          4 byte address
-###    %<label>          4 byte relative
-###    local_<label>     function-local
-###    string_<index>    string #<index>
+### Commentary:
 
-### elf32-body-exit-42.hex2: 32 bit elf body in hex2 for `exit 42'
+# elf32-body-exit-42.hex2: `exit 42' for arm-linux written in hex2
+# assembly, for usage with generic elf32-header.hex2 and
+# elf32-footer-single-main.hex.
+
+# This ELF binary contains a symbol table, which means that objdump and
+# gdb can be used to inspect and debug.
+
+### Code:
 
 # @200
 :ELF_text
 :_start
-# exit(42)
-
-~main ea                       # b main
-00 00 00
+^~main eb                      # bl main
+00 00 00 00
 00 00 00 00
 00 00 00 00
 
+# @210
 :main
-
-42 00 a0 e3                    # mov    $42 -> %r0
-01 70 a0 e3                    # mov    $0x1 -> %r7
-00 00 00 ef                    # swi 0
-
-00 00 00 00
+01 70 a0 e3                    # mov    r7,$0x1
+2a 00 a0 e3                    # mov    r0,$0x2a
+00 00 00 ef                    # swi    0
+03 f0 20 e3                    # wfi
 
 # @220
 :ELF_data
-65 78 69 74 34 32 20 64 61 74 61 20 68 65 72 65 # "exit42 data here"
+65 78 69 74 34 32 20 64 61 74 61 20 68 65 72 65 # exit42 data here"
+00
diff --git a/lib/arm-mes/elf32-body-hello-mes.hex2 b/lib/arm-mes/elf32-body-hello-mes.hex2
new file mode 100644
index 00000000..edc7b042
--- /dev/null
+++ b/lib/arm-mes/elf32-body-hello-mes.hex2
@@ -0,0 +1,59 @@
+### Copyright (C) 2017,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+### Copyright (C) 2019 Danny Milosavljevic <dannym@scratchpost.org>
+###
+### This file is part of GNU Mes.
+###
+### GNU Mes 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 3 of the License, or (at
+### your option) any later version.
+###
+### GNU Mes 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 GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
+
+### Commentary:
+
+# elf32-body-hello-mes.hex2: `exit 42' for arm-linux written in hex2
+# assembly, for usage with generic elf32-header.hex2 and
+# elf32-footer-single-main.hex.
+
+# This ELF binary contains a symbol table, which means that objdump and
+# gdb can be used to inspect and debug.
+
+### Code:
+
+# @200
+:ELF_text
+:_start
+^~main eb                      # bl main
+00 00 00 00
+00 00 00 00
+00 00 00 00
+
+# @210
+:main
+                               # print <hello>
+04 70 a0 e3                    # mov    r7, #4
+01 00 a0 e3                    # mov    r0, #1
+!hello 10 8f e2                # add    r1, pc, $(hello - pc)
+!bye>hello 20 a0 e3            # mov    r2, $(bye-hello)
+00 00 00 ef                    # swi    0
+
+                               # exit 0
+01 70 a0 e3                    # mov    r7, #1
+00 00 a0 e3                    # mov    r0, #0
+00 00 00 ef                    # swi    0
+03 f0 20 e3                    # wfi
+
+# @90
+:ELF_data
+:hello
+48 65 6c 6c 6f 2c 20 47        # Hello, G
+4e 55 20 4d 65 73 21 0a        # NU Mes!\n
+:bye
+:ELF_end
diff --git a/lib/arm-mes/elf32-header.hex2 b/lib/arm-mes/elf32-header.hex2
index 30ad0f65..e10dd44d 100644
--- a/lib/arm-mes/elf32-header.hex2
+++ b/lib/arm-mes/elf32-header.hex2
@@ -1,31 +1,39 @@
 ### Copyright (C) 2016 Jeremiah Orians
-### Copyright (C) 2017 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+### Copyright (C) 2017,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
 ### Copyright (C) 2019 Danny Milosavljevic <dannym@scratchpost.org>
-### This file is part of stage0.
 ###
-### stage0 is free software: you an redistribute it and/or modify
-### it under the terms of the GNU General Public License as published by
-### the Free Software Foundation, either version 3 of the License, or
-### (at your option) any later version.
+### This file is part of GNU Mes.
 ###
-### stage0 is distributed in the hope that it will be useful,
-### but WITHOUT ANY WARRANTY; without even the implied warranty of
+### GNU Mes 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 3 of the License, or (at
+### your option) any later version.
+###
+### GNU Mes 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 stage0.  If not, see <http://www.gnu.org/licenses/>.
+### along with GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
 
-### stage0's hex2 format for arm
-###    !<label>          1 byte relative
-###    $<label>          2 byte address
-###    @<label>          2 byte relative
-###    &<label>          4 byte address
-###    %<label>          4 byte relative
-###    local_<label>     function-local
-###    string_<index>    string #<index>
+### Commentary:
 
-### elf32-header-exit-42.hex2: 32 bit elf header in hex2 for `exit 42'
+# elf32-header.hex2: 32 bit elf header in hex2, with text segment, data
+# segment and symbol tables.
+
+# stage0's hex2 format for arm
+#    !<label>          1 byte relative
+#    $<label>          2 byte address
+#    @<label>          2 byte relative
+#    ~<label>          3 byte relative
+#    &<label>          4 byte address
+#    %<label>          4 byte relative
+#    local_<label>     function-local
+#    string_<index>    string #<index>
+#    ^                 align
+
+### Code:
 
 :ELF_base
 7F 45 4C 46                    # e_ident[EI_MAG0-3] ELF's magic number