Reverse Engineering for Beginners

CHAPTER 17. FLOATING-POINT UNIT CHAPTER 17. FLOATING-POINT UNIT
43 Status Word: 0x3000
44 TOP: 6
45 Control Word: 0x037f IM DM ZM OM UM PM
46 PC: Extended Precision (64-bits)
47 RC: Round to nearest
48 Tag Word: 0x0fff
49 Instruction Pointer: 0x73:0x080484a4
50 Operand Pointer: 0x7b:0xbffff118
51 Opcode: 0x0000
52 (gdb) ni
53 0x080484aa in d_max ()
54 (gdb) info float
55 R7: Valid 0x4000d999999999999800 +3.399999999999999911
56 =>R6: Valid 0x3fff9999999999999800 +1.199999999999999956
57 R5: Empty 0x00000000000000000000
58 R4: Empty 0x00000000000000000000
59 R3: Empty 0x00000000000000000000
60 R2: Empty 0x00000000000000000000
61 R1: Empty 0x00000000000000000000
62 R0: Empty 0x00000000000000000000
63
64 Status Word: 0x3000
65 TOP: 6
66 Control Word: 0x037f IM DM ZM OM UM PM
67 PC: Extended Precision (64-bits)
68 RC: Round to nearest
69 Tag Word: 0x0fff
70 Instruction Pointer: 0x73:0x080484a8
71 Operand Pointer: 0x7b:0xbffff118
72 Opcode: 0x0000
73 (gdb) disas $eip
74 Dump of assembler code for function d_max:
75 0x080484a0 <+0>: fldl 0x4(%esp)
76 0x080484a4 <+4>: fldl 0xc(%esp)
77 0x080484a8 <+8>: fxch %st(1)
78 => 0x080484aa <+10>: fucomi %st(1),%st
79 0x080484ac <+12>: fcmovbe %st(1),%st
80 0x080484ae <+14>: fstp %st(1)
81 0x080484b0 <+16>: ret
82 End of assembler dump.
83 (gdb) ni
84 0x080484ac in d_max ()
85 (gdb) info registers
86 eax 0x1 1
87 ecx 0xbffff1c4 -1073745468
88 edx 0x8048340 134513472
89 ebx 0xb7fbf000 -1208225792
90 esp 0xbffff10c 0xbffff10c
91 ebp 0xbffff128 0xbffff128
92 esi 0x0 0
93 edi 0x0 0
94 eip 0x80484ac 0x80484ac <d_max+12>
95 eflags 0x203 [ CF IF ]
96 cs 0x73 115
97 ss 0x7b 123
98 ds 0x7b 123
99 es 0x7b 123
100 fs 0x0 0
101 gs 0x33 51
102 (gdb) ni
103 0x080484ae in d_max ()
104 (gdb) info float
105 R7: Valid 0x4000d999999999999800 +3.399999999999999911
106 =>R6: Valid 0x4000d999999999999800 +3.399999999999999911
107 R5: Empty 0x00000000000000000000
108 R4: Empty 0x00000000000000000000
109 R3: Empty 0x00000000000000000000
110 R2: Empty 0x00000000000000000000
111 R1: Empty 0x00000000000000000000
112 R0: Empty 0x00000000000000000000