From 64b8b8403dc6e641f1033662365b44ae23479f75 Mon Sep 17 00:00:00 2001
From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Sun, 20 Mar 2022 13:40:58 +0000
Subject: [PATCH] add microwatt hello_world source

---
 hello_world/Makefile      |  34 ++++++++++++
 hello_world/head.S        | 107 ++++++++++++++++++++++++++++++++++++++
 hello_world/hello_world.c |  30 +++++++++++
 hello_world/powerpc.lds   |  13 +++++
 4 files changed, 184 insertions(+)
 create mode 100644 hello_world/Makefile
 create mode 100644 hello_world/head.S
 create mode 100644 hello_world/hello_world.c
 create mode 100644 hello_world/powerpc.lds

diff --git a/hello_world/Makefile b/hello_world/Makefile
new file mode 100644
index 0000000..dd51bd3
--- /dev/null
+++ b/hello_world/Makefile
@@ -0,0 +1,34 @@
+ARCH = $(shell uname -m)
+ifneq ("$(ARCH)", "ppc64")
+ifneq ("$(ARCH)", "ppc64le")
+	CROSS_COMPILE ?= powerpc64le-linux-gnu-
+endif
+endif
+
+CC = $(CROSS_COMPILE)gcc
+LD = $(CROSS_COMPILE)ld
+OBJCOPY = $(CROSS_COMPILE)objcopy
+
+CFLAGS = -Os -g -Wall -std=c99 -msoft-float -mno-string -mno-multiple -mno-vsx -mno-altivec -mlittle-endian -fno-stack-protector -mstrict-align -ffreestanding -fdata-sections -ffunction-sections -I../include
+ASFLAGS = $(CFLAGS)
+LDFLAGS = -T powerpc.lds
+
+all: hello_world.hex
+
+console.o: ../lib/console.c
+	$(CC) $(CPPFLAGS) $(CFLAGS) -c $< -o $@
+
+hello_world.elf: hello_world.o head.o console.o
+	$(LD) $(LDFLAGS) -o $@ $^
+
+hello_world.bin: hello_world.elf
+	$(OBJCOPY) -O binary $^ $@
+
+hello_world.hex: hello_world.bin
+	../scripts/bin2hex.py $^ > $@
+
+clean:
+	@rm -f *.o hello_world.elf hello_world.bin hello_world.hex
+distclean: clean
+	rm -f *~
+
diff --git a/hello_world/head.S b/hello_world/head.S
new file mode 100644
index 0000000..6357606
--- /dev/null
+++ b/hello_world/head.S
@@ -0,0 +1,107 @@
+/* Copyright 2013-2014 IBM Corp.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * 	http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+ * implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define STACK_TOP 0x2000
+
+#define FIXUP_ENDIAN						   \
+	tdi   0,0,0x48;	  /* Reverse endian of b . + 8		*/ \
+	b     191f;	  /* Skip trampoline if endian is good	*/ \
+	.long 0xa600607d; /* mfmsr r11				*/ \
+	.long 0x01006b69; /* xori r11,r11,1			*/ \
+	.long 0x05009f42; /* bcl 20,31,$+4			*/ \
+	.long 0xa602487d; /* mflr r10				*/ \
+	.long 0x14004a39; /* addi r10,r10,20			*/ \
+	.long 0xa64b5a7d; /* mthsrr0 r10			*/ \
+	.long 0xa64b7b7d; /* mthsrr1 r11			*/ \
+	.long 0x2402004c; /* hrfid				*/ \
+191:
+
+
+/* Load an immediate 64-bit value into a register */
+#define LOAD_IMM64(r, e)			\
+	lis     r,(e)@highest;			\
+	ori     r,r,(e)@higher;			\
+	rldicr  r,r, 32, 31;			\
+	oris    r,r, (e)@h;			\
+	ori     r,r, (e)@l;
+
+	.section ".head","ax"
+
+	/*
+	 * Microwatt currently enters in LE mode at 0x0, so we don't need to
+	 * do any endian fix ups>
+	 */
+	. = 0
+.global _start
+_start:
+	b	boot_entry
+
+	/* QEMU enters at 0x10 */
+	. = 0x10
+	FIXUP_ENDIAN
+	b	boot_entry
+
+	. = 0x100
+	FIXUP_ENDIAN
+	b	boot_entry
+
+.global boot_entry
+boot_entry:
+	/* setup stack */
+	LOAD_IMM64(%r1, STACK_TOP - 0x100)
+	LOAD_IMM64(%r12, main)
+	mtctr	%r12,
+	bctrl
+	b .
+
+#define EXCEPTION(nr)		\
+	.= nr			;\
+	b	.
+
+	/* More exception stubs */
+	EXCEPTION(0x300)
+	EXCEPTION(0x380)
+	EXCEPTION(0x400)
+	EXCEPTION(0x480)
+	EXCEPTION(0x500)
+	EXCEPTION(0x600)
+	EXCEPTION(0x700)
+	EXCEPTION(0x800)
+	EXCEPTION(0x900)
+	EXCEPTION(0x980)
+	EXCEPTION(0xa00)
+	EXCEPTION(0xb00)
+	EXCEPTION(0xc00)
+	EXCEPTION(0xd00)
+	EXCEPTION(0xe00)
+	EXCEPTION(0xe20)
+	EXCEPTION(0xe40)
+	EXCEPTION(0xe60)
+	EXCEPTION(0xe80)
+	EXCEPTION(0xf00)
+	EXCEPTION(0xf20)
+	EXCEPTION(0xf40)
+	EXCEPTION(0xf60)
+	EXCEPTION(0xf80)
+#if 0
+	EXCEPTION(0x1000)
+	EXCEPTION(0x1100)
+	EXCEPTION(0x1200)
+	EXCEPTION(0x1300)
+	EXCEPTION(0x1400)
+	EXCEPTION(0x1500)
+	EXCEPTION(0x1600)
+#endif
diff --git a/hello_world/hello_world.c b/hello_world/hello_world.c
new file mode 100644
index 0000000..0f08631
--- /dev/null
+++ b/hello_world/hello_world.c
@@ -0,0 +1,30 @@
+#include <stdint.h>
+#include <stdbool.h>
+
+#include "console.h"
+
+static char mw_logo[] =
+
+"\n"
+"   .oOOo.     \n"
+" .\"      \". \n"
+" ;  .mw.  ;   Microwatt, it works.\n"
+"  . '  ' .    \n"
+"   \\ || /    \n"
+"    ;..;      \n"
+"    ;..;      \n"
+"    `ww'   \n";
+
+int main(void)
+{
+	console_init();
+
+	puts(mw_logo);
+
+	while (1) {
+		unsigned char c = getchar();
+		putchar(c);
+		if (c == 13) // if CR send LF
+			putchar(10);
+	}
+}
diff --git a/hello_world/powerpc.lds b/hello_world/powerpc.lds
new file mode 100644
index 0000000..96bc6b9
--- /dev/null
+++ b/hello_world/powerpc.lds
@@ -0,0 +1,13 @@
+SECTIONS
+{
+	_start = .;
+	. = 0;
+	.head : {
+		KEEP(*(.head))
+ 	}
+	. = 0x1000;
+	.text : { *(.text) }
+	. = 0x1800;
+	.data : { *(.data) }
+	.bss : { *(.bss) }
+}
-- 
2.30.2