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.code16
#ifndef REGPARM
# error "This file assumes -mregparm=3 -DREGPARM=3"
#endif
.section ".text","ax"
.globl _start
.type _start,@function
_start:
# Align the stack and make sure the high half is zero
andl $0xfff8,%esp
# DS, ES points to the PSP at this point
pushw %es # Save PSP pointer
movw %cs,%ax
movw %ax,%ds
movw %ax,%es
# Clear the .bss
cld
xorl %eax,%eax
movw $__bss_start,%di
movw $__bss_end+3,%cx
subw %di,%cx
shrw $2,%cx
rep ; stosl
# Copy the command line into our own segment
popw %fs # FS -> PSP
movw $_cmdline,%di
movzbw %fs:0x80,%cx
movw $0x81,%si
fs ; rep ; movsb
# Already zero-terminated since we're writing into clean bss
# Compute argc and argv (assumes REGPARM)
movl $_cmdline,%edx
pushl %eax # Make space for argv
movl %esp,%eax
calll __parse_argv
pushl %eax # argc
# Initialize malloc
calll __init_memory_arena
# Now call main... (NOTE: gcc forces main to be regparm 0)
popl %eax # argc
popl %edx # argv
calll main
# Here %eax is the exit code, fall through into exit
.size _start,.-_start
.globl exit
.type exit,@function
exit:
# Exit code already in %eax
movb $0x4c,%ah # Terminate program
int $0x21
1: hlt
jmp 1b
.size exit,.-exit
.section ".bss","aw"
.balign 4
_cmdline:
.space 128
.size _cmdline,.-_cmdline
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