From 2a37f7dae6022e164163e6d9ea4a4bba8a369fe6 Mon Sep 17 00:00:00 2001
From: mashitianxia <u202014662@hust.edu.cn>
Date: Mon, 17 Apr 2023 22:43:00 +0800
Subject: [PATCH] =?UTF-8?q?d1:=20=E9=AA=8C=E8=AF=81magic=E6=98=AF=E5=90=A6?=
 =?UTF-8?q?=E6=AD=A3=E7=A1=AE=EF=BC=8C=E8=A7=A3=E6=9E=90c.j=E6=8C=87?=
 =?UTF-8?q?=E4=BB=A4?=
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Signed-off-by: mashitianxia <u202014662@hust.edu.cn>
---
 D1Image.bt | 31 +++++++++++++++++++++++++++++--
 1 file changed, 29 insertions(+), 2 deletions(-)

diff --git a/D1Image.bt b/D1Image.bt
index fd1a74c..b0cabaf 100644
--- a/D1Image.bt
+++ b/D1Image.bt
@@ -17,7 +17,7 @@ struct EgonHead;
 
 typedef struct {
     uint32 jump_instruction <format=hex, comment="address of jump_instruction">;
-    ubyte magic[8];
+    uint64 magic <format=hex>;
     uint32 checksum <format=hex, comment="checksum">;
     uint32 total_length <format=hex>;
     uint32 _head_size;
@@ -31,9 +31,13 @@ typedef struct {
 
 /**** PARSING CODE ****/
 LittleEndian();
-
 EgonHead head <bgcolor=cLtPurple>;
 
+local uint64 correct_magic = 0x3054422E4E4F4765;
+if (correct_magic != head.magic) {
+    Warning("wrong magic!");
+}  
+
 local uint32 opcode = head.jump_instruction & 0x7f;
 // 0x6f JAL opcode 
 if (opcode == 0x6f) 
@@ -53,3 +57,26 @@ if (opcode == 0x6f)
     }
     FSeek(off);
 }
+local uint16 c_ins = head.jump_instruction & 0xffff;
+local uint16 c_op = c_ins & 0x3;
+local uint16 c_funct3 = c_ins >> 13;
+if (c_op == 0x1 && c_funct3 == 0x5) {
+    local uint16 imm11 = (c_ins >> 12) & 0x1;
+    local uint16 imm4 = (c_ins >> 11) & 0x1;
+    local uint16 imm98 = (c_ins >> 9) & 0x3;
+    local uint16 imm10 = (c_ins >> 8) & 0x1;
+    local uint16 imm6 = (c_ins >> 7) & 0x1;
+    local uint16 imm7 = (c_ins >> 6) & 0x1;
+    local uint16 imm31 = (c_ins >> 3) & 0x7;
+    local uint16 imm5 = (c_ins >> 2) & 0x1;
+    local uint16 offset = (imm11 << 11) | (imm4 << 4) | (imm98 << 8) | (imm10 << 10) | (imm6 << 6)| (imm7 << 7)| (imm31 << 1) | (imm5 << 5);
+
+    local quad off = FTell();
+    if(offset < FileSize() && head.total_length <= FileSize()) {
+        FSeek(offset);
+        ubyte code[head.total_length - offset] <comment="code",bgcolor=cLtGreen>;
+    } else {
+        Warning("code appears to either overlap with header, exist after the end of the file or overlap with the end of the file!");
+    }
+    FSeek(off);
+}
-- 
Gitee