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Added checksum calculation to PnPBiosSupported().

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Patch by Petr Matousek.

svn path=/trunk/; revision=4964
This commit is contained in:
Eric Kohl 2003-06-25 13:56:04 +00:00
parent 676160308e
commit a547aaf0c5
1 changed files with 21 additions and 0 deletions
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21
freeldr/freeldr/arch/i386/i386pnp.S
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@ -40,6 +40,8 @@ EXTERN(_PnpBiosSupported)
pushl %edi
pushl %esi
pushl %ecx
pushl %edx
xorl %edi,%edi
@ -54,10 +56,27 @@ pnp_again:
cmp $0xFFFF0,%esi
je pnp_not_found
pnp_add:
addl $0x10,%esi
jmp pnp_again
pnp_found:
/* first calculate the checksum */
pushl %esi
pushl $0x21
popl %ecx
xorl %edx, %edx
pnp_loop:
lodsb
addb %al,%dl
loopl pnp_loop
testb %dl, %dl
popl %esi
jnz pnp_add
movl %esi,%edi
/* Calculate the bios entry point (far pointer) */
@ -74,6 +93,8 @@ pnp_found:
pnp_not_found:
movl %edi,%eax
popl %edx
popl %ecx
popl %esi
popl %edi