要提交的变更：

	新文件：   reference/stackframe/stackframe.cpp
	新文件：   reference/stackframe/stackframe.rs

reference/stackframe/stackframe.cpp

@@ -0,0 +1,76 @@
+#include <fmt/core.h>
+#include <utility>
+
+struct RegGenExcept {
+    size_t t0;      //0
+    size_t t1;      //8
+    size_t t2;      //16
+    size_t t3;      //24
+    size_t t4;      //32
+    size_t t5;      //40
+    size_t t6;      //48
+    size_t a0;      //56
+    size_t a1;      //64
+    size_t a2;      //72
+    size_t a3;      //80
+    size_t a4;      //88
+    size_t a5;      //96
+    size_t a6;      //104
+    size_t a7;      //112
+    size_t ra;      //120
+    size_t pc;      //128
+    size_t sstatus; //136
+    size_t sp;      //144
+};
+
+extern "C" {
+    void __rkplat_exception_handle(size_t cause, RegGenExcept &regs);
+}
+
+void __rkplat_exception_handle(size_t cause, RegGenExcept &regs) {
+    using std::make_pair;
+    auto [description,panic] = [&]{ switch (cause) {
+        case 0: return make_pair ("Instruction address misaligned.",true);
+        case 1 : return make_pair("Instruction access fault.",true);
+        case 2 : return make_pair("Illegal instruction.",true);
+        case 3 : return make_pair("Breakpoint.",false);
+        case 4 : return make_pair("Load address misaligned.",true);
+        case 5 : return make_pair("Load access fault.",true);
+        case 6 : return make_pair("Store/AMO address misaligned.",true);
+        case 7 : return make_pair("Store/AMO access fault.",true);
+        case 8 : return make_pair("Environment call from U-mode.",false);
+        case 9 : return make_pair("Environment call from S-mode.",false);
+        case 12: return make_pair("Instruction page fault.",true);
+        case 13: return make_pair("Load page fault.",true);
+        case 15: return make_pair("Store/AMO page fault.",true);
+        default: return make_pair("Unknown error.",true);
+    }}();
+    fmt::print("{} (code=0x{:02x})\n",description,cause);
+    fmt::print("registers:\n");
+    fmt::print("a0 = 0x{:016x}\n",regs.a0);
+    fmt::print("a1 = 0x{:016x}\n",regs.a1);
+    fmt::print("a2 = 0x{:016x}\n",regs.a2);
+    fmt::print("a3 = 0x{:016x}\n",regs.a3);
+    fmt::print("a4 = 0x{:016x}\n",regs.a4);
+    fmt::print("a5 = 0x{:016x}\n",regs.a5);
+    fmt::print("a6 = 0x{:016x}\n",regs.a6);
+    fmt::print("a7 = 0x{:016x}\n",regs.a7);
+    fmt::print("t0 = 0x{:016x}\n",regs.t0);
+    fmt::print("t1 = 0x{:016x}\n",regs.t1);
+    fmt::print("t2 = 0x{:016x}\n",regs.t2);
+    fmt::print("t3 = 0x{:016x}\n",regs.t3);
+    fmt::print("t4 = 0x{:016x}\n",regs.t4);
+    fmt::print("t5 = 0x{:016x}\n",regs.t5);
+    fmt::print("t6 = 0x{:016x}\n",regs.t6);
+    fmt::print("ra = 0x{:016x}\n",regs.ra);
+    fmt::print("sp = 0x{:016x}\n",regs.sp);
+    fmt::print("pc = 0x{:016x}\n",regs.pc);
+    if(cause != 1) 
+        fmt::print("instruction = 0x{:016x}\n",*(reinterpret_cast<size_t*>(regs.pc)));
+    if(panic)
+        abort();
+} 
+
+int main() {
+
+}

reference/stackframe/stackframe.rs

@@ -0,0 +1,74 @@
+#[repr(C)]
+#[derive(Debug)]
+#[derive(Default)]
+pub struct RegGenExcept {
+    pub t0: usize,      //0
+    pub t1: usize,      //8
+    pub t2: usize,      //16
+    pub t3: usize,      //24
+    pub t4: usize,      //32
+    pub t5: usize,      //40
+    pub t6: usize,      //48
+    pub a0: usize,      //56
+    pub a1: usize,      //64
+    pub a2: usize,      //72
+    pub a3: usize,      //80
+    pub a4: usize,      //88
+    pub a5: usize,      //96
+    pub a6: usize,      //104
+    pub a7: usize,      //112
+    pub ra: usize,      //120
+    pub pc: usize,      //128
+    pub sstatus: usize, //136
+    pub sp: usize,      //144
+}
+
+#[no_mangle]
+unsafe extern "C" fn __rkplat_exception_handle(cause: usize, regs: &mut RegGenExcept) {
+    let (description,panic) = match cause {
+        0 => ("Instruction address misaligned.",true),
+        1 => ("Instruction access fault.",true),
+        2 => ("Illegal instruction.",true),
+        3 => ("Breakpoint.",false),
+        4 => ("Load address misaligned.",true),
+        5 => ("Load access fault.",true),
+        6 => ("Store/AMO address misaligned.",true),
+        7 => ("Store/AMO access fault.",true),
+        8 => ("Environment call from U-mode.",false),
+        9 => ("Environment call from S-mode.",false),
+        12 => ("Instruction page fault.",true),
+        13 => ("Load page fault.",true),
+        15 => ("Store/AMO page fault.",true),
+        _ => ("Unknown error.",true),
+    };
+    println!("{} (code=0x{:02x})",description,cause);
+    println!("registers:");
+    println!("a0 = 0x{:016x}",regs.a0);
+    println!("a1 = 0x{:016x}",regs.a1);
+    println!("a2 = 0x{:016x}",regs.a2);
+    println!("a3 = 0x{:016x}",regs.a3);
+    println!("a4 = 0x{:016x}",regs.a4);
+    println!("a5 = 0x{:016x}",regs.a5);
+    println!("a6 = 0x{:016x}",regs.a6);
+    println!("a7 = 0x{:016x}",regs.a7);
+    println!("t0 = 0x{:016x}",regs.t0);
+    println!("t1 = 0x{:016x}",regs.t1);
+    println!("t2 = 0x{:016x}",regs.t2);
+    println!("t3 = 0x{:016x}",regs.t3);
+    println!("t4 = 0x{:016x}",regs.t4);
+    println!("t5 = 0x{:016x}",regs.t5);
+    println!("t6 = 0x{:016x}",regs.t6);
+    println!("ra = 0x{:016x}",regs.ra);
+    println!("sp = 0x{:016x}",regs.sp);
+    println!("pc = 0x{:016x}",regs.pc);
+    if cause != 1 {
+        println!("instruction = 0x{:016x}",*(regs.pc as *const usize));
+    }
+    if panic {
+        panic!();
+    }
+}
+
+fn main() {
+
+}