Merge remote branch 'erwan/master_new'

[profile/ivi/syslinux.git] / dos / crt0.S

diff --git a/dos/crt0.S b/dos/crt0.S
index 9d0b2f8..3be5712 100644 (file)
--- a/dos/crt0.S
+++ b/dos/crt0.S
@@ -3,28 +3,39 @@
 #ifndef REGPARM
 # 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
@@ -33,13 +44,13 @@ _start:
        # Initialize malloc
        calll __init_memory_arena
 
-       # Now call main...
+       # 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
@@ -51,3 +62,9 @@ exit:
 1:     hlt
        jmp 1b
        .size exit,.-exit
+
+       .section ".bss","aw"
+       .balign 4
+_cmdline:
+       .space 128
+       .size _cmdline,.-_cmdline