添加rtthread相关代码

riscv/startup/context.h

@@ -0,0 +1,49 @@
+
+#ifndef context_h__
+#define context_h__
+
+#include "stdint.h"
+
+typedef struct {
+  uint32_t ra;//x1  0
+  uint32_t sp;//x2  1
+  uint32_t gp;//x3  2
+  uint32_t tp;//x4  3
+  uint32_t t0;//x5  4
+  uint32_t t1;//x6  5
+  uint32_t t2;//x7  6
+  uint32_t t6;//x31 7
+  uint32_t s1;//x9  8
+  uint32_t a0;//x10 9
+  uint32_t a1;//x11 10
+  uint32_t a2;//x12 11
+  uint32_t a3;//x13 12
+  uint32_t a4;//x14 13
+  uint32_t a5;//x15 14
+  uint32_t a6;//x16 15
+  uint32_t a7;//x17 16
+
+  uint32_t s2;//x18  17
+  uint32_t s3;//x19  18
+  uint32_t s4;//x20  19
+  uint32_t s5;//x21  20
+  uint32_t s6;//x22  21
+  uint32_t s7;//x23  22
+  uint32_t s8;//x24  23
+  uint32_t s9;//x25  24
+  uint32_t s10;//x26 25
+  uint32_t s11;//x27 26
+  uint32_t t3;//x28  27
+  uint32_t t4;//x29  28
+  uint32_t t5;//x30  29
+  uint32_t s0;//fp(x8) 30
+
+  uint32_t mstatus;//31
+  uint32_t mepc;//32
+} stack_context;
+
+
+
+
+
+#endif