Add trap test

Author: object-Object

Makefile

@@ -46,7 +46,7 @@ build/%.out: build/%.o
 	riscv32-unknown-elf-ld --script=rust/mlogv32/link.x -o build/$*.out build/$*.o
 
 build/%.o: asm/%.s | build
-	riscv32-unknown-elf-gcc --compile -o build/$*.o asm/$*.s
+	riscv32-unknown-elf-gcc --compile -march=rv32ima_zicsr -o build/$*.o asm/$*.s
 
 src/%.mlog: src/%.mlog.jinja
 	python -m mlogv32.preprocessor -o src/$*.mlog src/$*.mlog.jinja

asm/trap.s

@@ -0,0 +1,14 @@
+.global _start
+_start:
+    la t0, trap
+    csrw mtvec, t0
+
+    ecall
+
+    .insn i CUSTOM_0, 0, zero, zero, 0 # halt
+
+trap:
+    csrr t0, mepc
+    addi t0, t0, 4
+    csrw mepc, t0
+    mret