Restructure the whole thing

It will be something more than just messing around with RISC-V stuff.

Signed-off-by: Miquel Sabaté Solà <mikisabate@gmail.com>

3 files changed, 57 insertions, 0 deletions

diff --git a/arch/riscv/bios/Makefile b/arch/riscv/bios/Makefile
new file mode 100644
index 0000000..60e3cc4
--- /dev/null
+++ b/arch/riscv/bios/Makefile
@@ -0,0 +1,25 @@
+NAME = hello
+
+CROSS_AS 	?= riscv64-suse-linux-as
+CROSS_LD 	?= riscv64-suse-linux-ld
+CROSS_DUMP	?= riscv64-suse-linux-objdump
+ASFLAGS  	 = -march=rv64g -mabi=lp64
+
+EMU ?= qemu-system-riscv64
+
+##
+# Targets
+
+.PHONY: run
+run: clean build
+	$(CROSS_DUMP) -D $(NAME)
+	$(EMU) -machine virt -bios hello
+
+.PHONY: build
+build:
+	$(CROSS_AS) $(ASFLAGS) -o $(NAME).o -c $(NAME).s
+	$(CROSS_LD) -T config.ld $(NAME).o -o $(NAME)
+
+.PHONY: clean
+clean:
+	@rm -f $(NAME).o $(NAME)
diff --git a/arch/riscv/bios/config.ld b/arch/riscv/bios/config.ld
new file mode 100644
index 0000000..085caa3
--- /dev/null
+++ b/arch/riscv/bios/config.ld
@@ -0,0 +1,9 @@
+MEMORY {
+  dram_space (rwx) : ORIGIN = 0x80000000, LENGTH = 128
+}
+
+SECTIONS {
+  .text : {
+    hello.o(.text.bios)
+  } > dram_space
+}
diff --git a/arch/riscv/bios/hello.s b/arch/riscv/bios/hello.s
new file mode 100644
index 0000000..f3aa20a
--- /dev/null
+++ b/arch/riscv/bios/hello.s
@@ -0,0 +1,23 @@
+# From: https://github.com/qemu/qemu/blob/23fa74974d8c96bc95cbecc0d4e2d90f984939f6/hw/riscv/virt.c#L82.
+.set QEMU_UART0_ADDRESS, 0x10000000
+
+.global _start
+.section .text.bios
+
+_start:	li a0, 0x68
+	li a1, QEMU_UART0_ADDRESS
+	sb a0, (a1) # 'h'
+
+	li a0, 0x65
+	sb a0, (a1) # 'e'
+
+	li a0, 0x6C
+	sb a0, (a1) # 'l'
+
+	li a0, 0x6C
+	sb a0, (a1) # 'l'
+
+	li a0, 0x6F
+	sb a0, (a1) # 'o'
+
+loop:	j loop