The start of the project -- A MicroDOS

feat: Initial bare-metal RISC-V boot with UART

1 files changed, 28 insertions, 0 deletions

diff --git a/src/boot/entry.S b/src/boot/entry.S
new file mode 100644
index 0000000..1a6f6b8
--- /dev/null
+++ b/src/boot/entry.S
@@ -0,0 +1,28 @@
+.section .text.entry
+.globl _start
+
+_start:
+    csrr t0, mhartid
+    bnez t0, .L_park_harts
+
+    la sp, _stack_top
+
+    la a0, _bss_start
+    la a1, _bss_end
+    bge a0, a1, .L_call_main
+
+.L_clear_bss:
+    sd zero, (a0)
+    addi a0, a0, 8
+    blt a0, a1, .L_clear_bss
+
+.L_call_main:
+    call kernel_main
+
+.L_infinite_loop:
+    wfi
+    j .L_infinite_loop
+
+.L_park_harts:
+    wfi
+    j .L_park_harts
\ No newline at end of file