126 lines
2.7 KiB
ArmAsm
126 lines
2.7 KiB
ArmAsm
/* This is the C run-time start-off routine. It's job is to take the */
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/* arguments as put on the stack by EXEC, and to parse them and set them up the */
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/* way _main expects them. */
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/* It also initializes environ when this variable isn't defined by the */
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/* programmer. The detection of whether environ belong to us is rather */
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/* simplistic. We simply check for some magic value, but there is no other */
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/* way. */
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#include <machine/vm.h>
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.globl begtext, begdata, begbss
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.text
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begtext:
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#ifdef __ACK__
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.rom
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#else
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.data
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#endif
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begrom:
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.data
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begdata:
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.bss
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begbss:
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.globl crtso, __penviron, __penvp, ___prognamep, ___argc
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.globl __minix_datastart, __minix_mainjump, __minix_unmapzero
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.extern _main, _exit
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#if defined(__ELF__)
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.section .init
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#else
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.text
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#endif
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#if defined(__ELF__)
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.globl __start
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__start:
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#endif
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crtso:
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xorl %ebp, %ebp /* clear for backtrace of core files */
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movl (%esp), %eax /* argc */
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leal 4(%esp), %edx /* argv */
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leal 8(%esp,%eax,4), %ecx /* envp */
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/* Test if environ is in the initialized data area and is set to our */
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/* magic number. If so then it is not redefined by the user. */
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movl $_environ, %ebx
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cmpl $__edata, %ebx /* within initialized data? */
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jae 0f
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testb $3, %bl /* aligned? */
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jne 0f
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cmpl $0x53535353, (%ebx) /* is it our environ? */
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jne 0f
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movl %ebx, __penviron /* _penviron = &environ; */
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0:
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movl __penviron, %ebx
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movl %ecx, (%ebx) /* *_penviron = envp; */
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/* Save argv[] and argc. This is so that we can return
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* argv[0] in the future, without having to check whether
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* argv can be dereferenced safely now.
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*/
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mov %edx, (___prognamep)
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mov %eax, (___argc)
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push %ecx /* push envp */
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push %edx /* push argv */
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push %eax /* push argc */
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jmp __minix_mainjump
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.balign I386_PAGE_SIZE
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__minix_mainjump:
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/* unmap zero pages */
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call __minix_unmapzero
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call _main /* main(argc, argv, envp) */
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push %eax /* push exit status */
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call _exit
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hlt /* force a trap if exit fails */
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__minix_unmapzero:
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/* unmap 0-page code */
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push $I386_PAGE_SIZE
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push $crtso
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call _munmap_text /* unmap_text(crtso, I386_PAGE_SIZE) */
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add $8, %esp
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#ifdef __ACK__
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/*
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* ack uses separate segments for text and data by default. We have a
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* common segment when compiling using any other compiler
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*/
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/* unmap 0-page data */
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push $I386_PAGE_SIZE
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push $romstart
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call _munmap /* munmap(romstart, I386_PAGE_SIZE) */
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add $8, %esp
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#endif
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ret
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#ifdef __ACK__
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.rom
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romstart:
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.space I386_PAGE_SIZE
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__minix_datastart:
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.space 4
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#endif
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.data
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__penviron:
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.long __penvp /* Pointer to environ, or hidden pointer */
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.bss
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___prognamep:
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.space 4
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___argc:
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.space 4
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.lcomm __penvp, 4 /* Hidden environment vector */
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.extern endtext /* Force loading of end labels. */
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