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-rw-r--r--dos/crt0.S29
1 files changed, 23 insertions, 6 deletions
diff --git a/dos/crt0.S b/dos/crt0.S
index 62ab80ff..3be57125 100644
--- a/dos/crt0.S
+++ b/dos/crt0.S
@@ -4,27 +4,38 @@
# error "This file assumes -mregparm=3 -DREGPARM=3"
#endif
- .section ".init","ax"
+ .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 $_end+3,%cx
+ 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)
- xorl %edx,%edx
- movzbw 0x80,%bx
- movb %dl,0x81(%bx) # Zero-terminate string
- movb $0x81,%dl
+ movl $_cmdline,%edx
pushl %eax # Make space for argv
movl %esp,%eax
calll __parse_argv
@@ -51,3 +62,9 @@ exit:
1: hlt
jmp 1b
.size exit,.-exit
+
+ .section ".bss","aw"
+ .balign 4
+_cmdline:
+ .space 128
+ .size _cmdline,.-_cmdline