removes firmwares to just keep BSP

env/iss/init.c

@@ -0,0 +1,107 @@
+#include <stdint.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include "platform.h"
+#include "encoding.h"
+
+extern int main(int argc, char** argv);
+extern void trap_entry();
+
+static unsigned long mtime_lo(void)
+{
+    unsigned long ret;
+    __asm volatile("rdtime %0":"=r"(ret));
+    return ret;
+}
+
+
+#if __riscv_xlen==32
+
+static uint32_t mtime_hi(void)
+{
+    unsigned long ret;
+    __asm volatile("rdtimeh %0":"=r"(ret));
+    return ret;
+}
+
+uint64_t get_timer_value()
+{
+  while (1) {
+    uint32_t hi = mtime_hi();
+    uint32_t lo = mtime_lo();
+    if (hi == mtime_hi())
+      return ((uint64_t)hi << 32) | lo;
+  }
+}
+
+#elif __riscv_xlen==64
+
+uint64_t get_timer_value()
+{
+  return mtime_lo();
+}
+
+#endif
+
+unsigned long get_timer_freq()
+{
+  return 32768;
+}
+
+unsigned long get_cpu_freq()
+{
+  return 10000000;
+}
+
+void init_pll(void){
+
+}
+
+#ifdef USE_PLIC
+extern void handle_m_ext_interrupt();
+#endif
+
+#ifdef USE_M_TIME
+extern void handle_m_time_interrupt();
+#endif
+
+uintptr_t handle_trap(uintptr_t mcause, uintptr_t epc)
+{
+  if (0){
+#ifdef USE_PLIC
+    // External Machine-Level interrupt from PLIC
+  } else if ((mcause & MCAUSE_INT) && ((mcause & MCAUSE_CAUSE) == IRQ_M_EXT)) {
+    handle_m_ext_interrupt();
+#endif
+#ifdef USE_M_TIME
+    // External Machine-Level interrupt from PLIC
+  } else if ((mcause & MCAUSE_INT) && ((mcause & MCAUSE_CAUSE) == IRQ_M_TIMER)){
+    handle_m_time_interrupt();
+#endif
+  }
+  else {
+    write(1, "trap\n", 5);
+    _exit(1 + mcause);
+  }
+  return epc;
+}
+
+void _init()
+{
+  
+#ifndef NO_INIT
+  init_pll();
+  printf("core freq at %d Hz\n", get_cpu_freq());
+  write_csr(mtvec, &trap_entry);
+  if (read_csr(misa) & (1 << ('F' - 'A'))) { // if F extension is present
+    write_csr(mstatus, MSTATUS_FS); // allow FPU instructions without trapping
+    write_csr(fcsr, 0); // initialize rounding mode, undefined at reset
+  }
+#endif
+  
+}
+
+void _fini()
+{
+}