1 /* ----------------------------------------------------------------------- 2 * 3 * Copyright 2003-2008 H. Peter Anvin - All Rights Reserved 4 * 5 * Permission is hereby granted, free of charge, to any person 6 * obtaining a copy of this software and associated documentation 7 * files (the "Software"), to deal in the Software without 8 * restriction, including without limitation the rights to use, 9 * copy, modify, merge, publish, distribute, sublicense, and/or 10 * sell copies of the Software, and to permit persons to whom 11 * the Software is furnished to do so, subject to the following 12 * conditions: 13 * 14 * The above copyright notice and this permission notice shall 15 * be included in all copies or substantial portions of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 18 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES 19 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 20 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT 21 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 22 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 23 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 24 * OTHER DEALINGS IN THE SOFTWARE. 25 * 26 * ----------------------------------------------------------------------- */ 27 28 /* 29 * COM32 start up code - must be linked first in the binary 30 */ 31 32 /* Number of arguments in our version of the entry structure */ 33 #define COM32_ARGS 9 34 35 .section ".init","ax" 36 .globl _start 37 .type _start, @function 38 _start: 39 /* This first instruction acts as COM32R magic number */ 40 movl $0x21cd4cfe,%eax 41 42 /* Upwards string operations */ 43 cld 44 45 /* Find our own location */ 46 call 1f 47 1: popl %ebx 48 addl $_GLOBAL_OFFSET_TABLE_ + (. - 1b), %ebx 49 50 /* Process relocations (which overlay the .bss segment) */ 51 leal _edata@GOTOFF(%ebx),%esi 52 leal _start@GOTOFF(%ebx),%edx 53 2: lodsl 54 andl %eax,%eax 55 jz 3f 56 addl %edx,(%eax,%edx) 57 jmp 2b 58 3: 59 /* Relocate the GOT (is this right?) */ 60 leal __got_start@GOTOFF(%ebx),%esi 61 leal __got_end@GOTOFF(%ebx),%edi 62 4: 63 addl %edx,(%esi) 64 addl $4,%esi 65 cmpl %edi,%esi 66 jb 4b 67 68 /* Zero the .bss segment */ 69 xorl %eax,%eax 70 leal __bss_start@GOTOFF(%ebx),%edi 71 leal _end+3@GOTOFF(%ebx),%ecx 72 subl %edi,%ecx 73 shrl $2,%ecx 74 rep ; stosl 75 76 /* Copy COM32 invocation parameters */ 77 leal 4(%esp),%esi # Argument list 78 leal __com32@GOTOFF(%ebx),%edi 79 movl $(COM32_ARGS),%ecx 80 movl %esp,-4(%edi) # Save the initial stack ptr 81 cmpl (%esi),%ecx 82 jbe 5f 83 movl (%esi),%ecx 84 5: inc %ecx # Copy the argument count, too 85 rep ; movsl 86 87 /* Parse the command line (assumes REGPARM) */ 88 movl __com32+4@GOTOFF(%ebx),%edx # Command line 89 pushl %edx # Make space for argv 90 movl %esp,%eax 91 call __parse_argv 92 pushl %eax # Save argc 93 94 /* Look for library initialization functions */ 95 leal __ctors_start@GOTOFF(%ebx),%esi 96 leal __ctors_end@GOTOFF(%ebx),%edi 97 6: 98 cmpl %edi,%esi 99 jae 7f 100 call *(%esi) 101 addl $4,%esi 102 jmp 6b 103 /* 104 * Actually run main. This assumes REGPARM is used!!!! 105 */ 106 7: 107 popl %eax # argc 108 popl %edx # argv 109 call main 110 call *__exit_handler@GOTOFF(%ebx) 111 hlt 112 .size _start, .-_start 113 114 .bss 115 .globl __entry_esp 116 __entry_esp: .space 4 117 .globl __com32 118 __com32: .space 4*(COM32_ARGS+1) 119
