被期末考硬控了很久，终于稍微有点空了，打算先试着把CSAPP写完。虽然写得很混子，但是暂时先记着，总比没有来得好。
版本：XieGuochao/csapp: The docker source and materials for CS:APP labs (github.com)
Phase4
这里充当笔记记录一下phase4的分析过程，phase1-3比较简单，之后也许会补上，也许不会。
以下是对phase4汇编代码的一些注释，本来写了一大段结果忘记保存，破防之后决定参考一下别人的博客好了。
Dump of assembler code for function phase_4:
=> 0x000000000040100c <+0>: sub $0x18,%rsp//栈空间扩展24
0x0000000000401010 <+4>: lea 0xc(%rsp),%rcx//第二个参数
0x0000000000401015 <+9>: lea 0x8(%rsp),%rdx//第一个参数
0x000000000040101a <+14>: mov $0x4025cf,%esi//
0x000000000040101f <+19>: mov $0x0,%eax
0x0000000000401024 <+24>: callq 0x400bf0 <__isoc99_sscanf@plt>
0x0000000000401029 <+29>: cmp $0x2,%eax
0x000000000040102c <+32>: jne 0x401035 <phase_4+41>//参数数量不等于2，爆炸
0x000000000040102e <+34>: cmpl $0xe,0x8(%rsp)
0x0000000000401033 <+39>: jbe 0x40103a <phase_4+46>//param1小于等于14，否则爆炸
0x0000000000401035 <+41>: callq 0x40143a <explode_bomb>
0x000000000040103a <+46>: mov $0xe,%edx
0x000000000040103f <+51>: mov $0x0,%esi
0x0000000000401044 <+56>: mov 0x8(%rsp),%edi//为func4准备参数（d1,0,14）
0x0000000000401048 <+60>: callq 0x400fce <func4>
0x000000000040104d <+65>: test %eax,%eax//测试返回值是否为0
0x000000000040104f <+67>: jne 0x401058 <phase_4+76>
0x0000000000401051 <+69>: cmpl $0x0,0xc(%rsp)//d2为0
0x0000000000401056 <+74>: je 0x40105d <phase_4+81>
0x0000000000401058 <+76>: callq 0x40143a <explode_bomb>
0x000000000040105d <+81>: add $0x18,%rsp
0x0000000000401061 <+85>: retq Dump of assembler code for function func4://edi=x,esi=y,edx=14
=> 0x0000000000400fce <+0>: sub $0x8,%rsp
0x0000000000400fd2 <+4>: mov %edx,%eax //eax=14
0x0000000000400fd4 <+6>: sub %esi,%eax //14-0
0x0000000000400fd6 <+8>: mov %eax,%ecx //ecx=14
0x0000000000400fd8 <+10>: shr $0x1f,%ecx//14逻辑右移31位（为0）
0x0000000000400fdb <+13>: add %ecx,%eax//14+0
0x0000000000400fdd <+15>: sar %eax//14/2（算术右移一位）
0x0000000000400fdf <+17>: lea (%rax,%rsi,1),%ecx//???
0x0000000000400fe2 <+20>: cmp %edi,%ecx
0x0000000000400fe4 <+22>: jle 0x400ff2 <func4+36>//x<=7则跳转至+43，否则进入递归
0x0000000000400fe6 <+24>: lea -0x1(%rcx),%edx
0x0000000000400fe9 <+27>: callq 0x400fce <func4>
0x0000000000400fee <+32>: add %eax,%eax
0x0000000000400ff0 <+34>: jmp 0x401007 <func4+57>
0x0000000000400ff2 <+36>: mov $0x0,%eax
0x0000000000400ff7 <+41>: cmp %edi,%ecx
0x0000000000400ff9 <+43>: jge 0x401007 <func4+57>//大于等于7则函数返回0
0x0000000000400ffb <+45>: lea 0x1(%rcx),%esi
0x0000000000400ffe <+48>: callq 0x400fce <func4>
0x0000000000401003 <+53>: lea 0x1(%rax,%rax,1),%eax
0x0000000000401007 <+57>: add $0x8,%rsp
0x000000000040100b <+61>: retq Phase5
Dump of assembler code for function phase_5:
=> 0x0000000000401062 <+0>: push %rbx
0x0000000000401063 <+1>: sub $0x20,%rsp
0x0000000000401067 <+5>: mov %rdi,%rbx
0x000000000040106a <+8>: mov %fs:0x28,%rax
0x0000000000401073 <+17>: mov %rax,0x18(%rsp)
0x0000000000401078 <+22>: xor %eax,%eax
0x000000000040107a <+24>: callq 0x40131b <string_length>
0x000000000040107f <+29>: cmp $0x6,%eax
0x0000000000401082 <+32>: je 0x4010d2 <phase_5+112>
0x0000000000401084 <+34>: callq 0x40143a <explode_bomb>
0x0000000000401089 <+39>: jmp 0x4010d2 <phase_5+112>
0x000000000040108b <+41>: movzbl (%rbx,%rax,1),%ecx
0x000000000040108f <+45>: mov %cl,(%rsp)
0x0000000000401092 <+48>: mov (%rsp),%rdx
0x0000000000401096 <+52>: and $0xf,%edx
0x0000000000401099 <+55>: movzbl 0x4024b0(%rdx),%edx
0x00000000004010a0 <+62>: mov %dl,0x10(%rsp,%rax,1)
0x00000000004010a4 <+66>: add $0x1,%rax
0x00000000004010a8 <+70>: cmp $0x6,%rax
0x00000000004010ac <+74>: jne 0x40108b <phase_5+41>
0x00000000004010ae <+76>: movb $0x0,0x16(%rsp)
0x00000000004010b3 <+81>: mov $0x40245e,%esi
0x00000000004010b8 <+86>: lea 0x10(%rsp),%rdi
--Type <RET> for more, q to quit, c to continue without paging--c
0x00000000004010bd <+91>: callq 0x401338 <strings_not_equal>
0x00000000004010c2 <+96>: test %eax,%eax
0x00000000004010c4 <+98>: je 0x4010d9 <phase_5+119>
0x00000000004010c6 <+100>: callq 0x40143a <explode_bomb>
0x00000000004010cb <+105>: nopl 0x0(%rax,%rax,1)
0x00000000004010d0 <+110>: jmp 0x4010d9 <phase_5+119>
0x00000000004010d2 <+112>: mov $0x0,%eax
0x00000000004010d7 <+117>: jmp 0x40108b <phase_5+41>
0x00000000004010d9 <+119>: mov 0x18(%rsp),%rax
0x00000000004010de <+124>: xor %fs:0x28,%rax
0x00000000004010e7 <+133>: je 0x4010ee <phase_5+140>
0x00000000004010e9 <+135>: callq 0x400b30 <__stack_chk_fail@plt>
0x00000000004010ee <+140>: add $0x20,%rsp
0x00000000004010f2 <+144>: pop %rbx
0x00000000004010f3 <+145>: retq
End of assembler dump.Phase6
Dump of assembler code for function phase_6:
0x00000000004010f4 <+0>: push %r14
0x00000000004010f6 <+2>: push %r13
0x00000000004010f8 <+4>: push %r12
0x00000000004010fa <+6>: push %rbp
0x00000000004010fb <+7>: push %rbx
0x00000000004010fc <+8>: sub $0x50,%rsp//r14
0x0000000000401100 <+12>: mov %rsp,%r13
0x0000000000401103 <+15>: mov %rsp,%rsi
0x0000000000401106 <+18>: callq 0x40145c <read_six_numbers>
0x000000000040110b <+23>: mov %rsp,%r14 //rsp->r14
0x000000000040110e <+26>: mov $0x0,%r12d //r12d->0
0x0000000000401114 <+32>: mov %r13,%rbp //r13->rbp
0x0000000000401117 <+35>: mov 0x0(%r13),%eax
0x000000000040111b <+39>: sub $0x1,%eax
0x000000000040111e <+42>: cmp $0x5,%eax//eax<5 //参数小于6
0x0000000000401121 <+45>: jbe 0x401128 <phase_6+52>
0x0000000000401123 <+47>: callq 0x40143a <explode_bomb>
0x0000000000401128 <+52>: add $0x1,%r12d //r12d=1//循环开始
0x000000000040112c <+56>: cmp $0x6,%r12d//大循环 循环六次
0x0000000000401130 <+60>: je 0x401153 <phase_6+95>
0x0000000000401132 <+62>: mov %r12d,%ebx //ebx=1
; 0x0000000000401135 <+65>: movslq %ebx,%rax //rax=1 //循环开始
; 0x0000000000401138 <+68>: mov (%rsp,%rax,4),%eax //换下一个参数
; 0x000000000040113b <+71>: cmp %eax,0x0(%rbp)
; 0x000000000040113e <+74>: jne 0x401145 <phase_6+81>
; 0x0000000000401140 <+76>: callq 0x40143a <explode_bomb>
; 0x0000000000401145 <+81>: add $0x1,%ebx//ebx+=1
; 0x0000000000401148 <+84>: cmp $0x5,%ebx
; 0x000000000040114b <+87>: jle 0x401135 <phase_6+65>//小循环 循环五次 比较每个数是否相等
0x000000000040114d <+89>: add $0x4,%r13
0x0000000000401151 <+93>: jmp 0x401114 <phase_6+32>
0x0000000000401153 <+95>: lea 0x18(%rsp),%rsi
0x0000000000401158 <+100>: mov %r14,%rax//r14->rax
0x000000000040115b <+103>: mov $0x7,%ecx
0x0000000000401160 <+108>: mov %ecx,%edx
0x0000000000401162 <+110>: sub (%rax),%edx//7-a[i]
0x0000000000401164 <+112>: mov %edx,(%rax)
0x0000000000401166 <+114>: add $0x4,%rax//下一个参数
0x000000000040116a <+118>: cmp %rsi,%rax //rsi=?
0x000000000040116d <+121>: jne 0x401160 <phase_6+108>//循环结束
0x000000000040116f <+123>: mov $0x0,%esi
0x0000000000401174 <+128>: jmp 0x401197 <phase_6+163>
0x0000000000401176 <+130>: mov 0x8(%rdx),%rdx
0x000000000040117a <+134>: add $0x1,%eax//rdx+16取出链表下一个数的地址
0x000000000040117d <+137>: cmp %ecx,%eax
0x000000000040117f <+139>: jne 0x401176 <phase_6+130>
0x0000000000401181 <+141>: jmp 0x401188 <phase_6+148>
0x0000000000401183 <+143>: mov $0x6032d0,%edx
0x0000000000401188 <+148>: mov %rdx,0x20(%rsp,%rsi,2)//
0x000000000040118d <+153>: add $0x4,%rsi
0x0000000000401191 <+157>: cmp $0x18,%rsi
0x0000000000401195 <+161>: je 0x4011ab <phase_6+183>
0x0000000000401197 <+163>: mov (%rsp,%rsi,1),%ecx
0x000000000040119a <+166>: cmp $0x1,%ecx
0x000000000040119d <+169>: jle 0x401183 <phase_6+143>
0x000000000040119f <+171>: mov $0x1,%eax
0x00000000004011a4 <+176>: mov $0x6032d0,%edx
0x00000000004011a9 <+181>: jmp 0x401176 <phase_6+130>
0x00000000004011ab <+183>: mov 0x20(%rsp),%rbx
0x00000000004011b0 <+188>: lea 0x28(%rsp),%rax
0x00000000004011b5 <+193>: lea 0x50(%rsp),%rsi
0x00000000004011ba <+198>: mov %rbx,%rcx
0x00000000004011bd <+201>: mov (%rax),%rdx
0x00000000004011c0 <+204>: mov %rdx,0x8(%rcx)
0x00000000004011c4 <+208>: add $0x8,%rax
0x00000000004011c8 <+212>: cmp %rsi,%rax
0x00000000004011cb <+215>: je 0x4011d2 <phase_6+222>
0x00000000004011cd <+217>: mov %rdx,%rcx
0x00000000004011d0 <+220>: jmp 0x4011bd <phase_6+201>
0x00000000004011d2 <+222>: movq $0x0,0x8(%rdx)
0x00000000004011da <+230>: mov $0x5,%ebp
0x00000000004011df <+235>: mov 0x8(%rbx),%rax
0x00000000004011e3 <+239>: mov (%rax),%eax
0x00000000004011e5 <+241>: cmp %eax,(%rbx)
0x00000000004011e7 <+243>: jge 0x4011ee <phase_6+250>//旧的大于新的
0x00000000004011e9 <+245>: callq 0x40143a <explode_bomb>
0x00000000004011ee <+250>: mov 0x8(%rbx),%rbx
0x00000000004011f2 <+254>: sub $0x1,%ebp
0x00000000004011f5 <+257>: jne 0x4011df <phase_6+235>
0x00000000004011f7 <+259>: add $0x50,%rsp
0x00000000004011fb <+263>: pop %rbx
0x00000000004011fc <+264>: pop %rbp
0x00000000004011fd <+265>: pop %r12
0x00000000004011ff <+267>: pop %r13
0x0000000000401201 <+269>: pop %r14
0x0000000000401203 <+271>: retq 
