add .text.startup section

src/bh_cpu.v

@@ -479,6 +479,8 @@ always @(posedge clk) begin: pipeline_update
         end
         
     end else begin
+        // $display("%0t:\tPC=0x%h", $time, s_if_next_pc);
+
         // IF
         if (!s_if_stall) begin
             r_if_pc     <= s_if_next_pc;

tests/test_c/tb.ld

@@ -1,5 +1,4 @@
 OUTPUT_ARCH( "riscv" )
-ENTRY(_start)
 
 MEMORY
 {
@@ -14,6 +13,7 @@ SECTIONS
     {
         /* . = ALIGN(4); */
         _text = .;
+        *(.text.startup)
         *(.text*)
         *(.rodata*)
         _etext = .;

tests/test_c/test.S

@@ -1,9 +1,17 @@
 .global _start
 
+.section .text.startup  # start vector 
+    j       _start
+    nop
+    nop
+    nop
+    nop
+    nop
+
 .text
 _start:
-
     addi    a0, zero, 0x134
+    addi    a1, zero, 0x0
     nop
     nop
     nop