1 ; This code is UNTESTED, and almost certainly DOES NOT WORK! 2 ; Do NOT use this as an example of how to write AMD64 shared libraries! 3 ; This code is simply to test the AMD64 ELF WRT relocations. 4 5 ; This file should test the following: 6 ; [1] Define and export a global text-section symbol 7 ; [2] Define and export a global data-section symbol 8 ; [3] Define and export a global BSS-section symbol 9 ; [4] Define a non-global text-section symbol 10 ; [5] Define a non-global data-section symbol 11 ; [6] Define a non-global BSS-section symbol 12 ; [7] Define a COMMON symbol 13 ; [8] Define a NASM local label 14 ; [9] Reference a NASM local label 15 ; [10] Import an external symbol 16 ; [11] Make a PC-relative call to an external symbol 17 ; [12] Reference a text-section symbol in the text section 18 ; [13] Reference a data-section symbol in the text section 19 ; [14] Reference a BSS-section symbol in the text section 20 ; [15] Reference a text-section symbol in the data section 21 ; [16] Reference a data-section symbol in the data section 22 ; [17] Reference a BSS-section symbol in the data section 23 24 [BITS 64] 25 [GLOBAL lrotate:function] ; [1] 26 [GLOBAL greet:function] ; [1] 27 [GLOBAL asmstr:data asmstr.end-asmstr] ; [2] 28 [GLOBAL textptr:data 4] ; [2] 29 [GLOBAL selfptr:data 4] ; [2] 30 [GLOBAL integer:data 4] ; [3] 31 [EXTERN printf] ; [10] 32 [COMMON commvar 4:4] ; [7] 33 [EXTERN _GLOBAL_OFFSET_TABLE_] 34 35 [SECTION .text] 36 37 ; prototype: long lrotate(long x, int num); 38 lrotate: ; [1] 39 push rbp 40 mov rbp,rsp 41 mov rax,[rbp+8] 42 mov rcx,[rbp+12] 43 .label rol rax,1 ; [4] [8] 44 loop .label ; [9] [12] 45 mov rsp,rbp 46 pop rbp 47 ret 48 49 ; prototype: void greet(void); 50 greet push rbx ; we'll use RBX for GOT, so save it 51 mov rbx,[integer wrt ..gotpcrel wrt rip] 52 mov rax,[rbx] ; [14] 53 inc rax 54 mov rbx,[_GLOBAL_OFFSET_TABLE_ wrt ..gotpcrel wrt rip] 55 mov [rbx+localint wrt ..got],eax ; [14] 56 mov rax,[rbx+commvar wrt ..got] 57 push qword [rax] 58 mov rax,[rbx+localptr wrt ..got] ; [13] 59 push qword [rax] 60 mov rax,[rbx+integer wrt ..got] ; [1] [14] 61 push qword [rax] 62 lea rax,[rbx+printfstr wrt ..got] 63 push rax ; [13] 64 call printf wrt ..plt ; [11] 65 add rsp,16 66 pop rbx 67 ret 68 69 [SECTION .data] 70 71 ; a string 72 asmstr db 'hello, world', 0 ; [2] 73 .end 74 75 ; a string for Printf 76 printfstr db "integer==%d, localint==%d, commvar=%d" 77 db 10, 0 78 79 ; some pointers 80 localptr dd localint ; [5] [17] 81 textptr dd greet wrt ..sym ; [15] 82 selfptr dd selfptr wrt ..sym ; [16] 83 84 [SECTION .bss] 85 86 ; an integer 87 integer resd 1 ; [3] 88 89 ; a local integer 90 localint resd 1 ; [6] 91
