Add ESP32C3 RISC-V stub
diff --git a/src/kernel/riscv32/boot.s b/src/kernel/riscv32/boot.s
new file mode 100644
index 0000000..6578eba
--- /dev/null
+++ b/src/kernel/riscv32/boot.s
@@ -0,0 +1,21 @@
+ .equ STACK_SIZE, 8192
+
+ .global _start
+
+_start:
+ csrr t0, mhartid
+ slli t0, t0, 10 # mhartid << 10
+ la sp, stacks + STACK_SIZE # set up space for hart stacks
+ add sp, sp, t0 # sp += (mhartid << 10)
+
+ ## For now, only run on hart 0
+ csrr a0, mhartid # pass hart id to kmain
+ bnez a0, .end
+ j kmain
+
+.end:
+ wfi
+ j .end
+
+stacks:
+ .skip STACK_SIZE * 4 # Allocate stack space for each hart