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bootstrap code fails
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Are you clobberng your Segment register on purpose?
this should be more like
Asm Syntax (Toggle Plain Text)
Asm Syntax (Toggle Plain Text)
Last edited by wildgoose; Sep 14th, 2009 at 4:53 pm.
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Originally Posted by wildgoose 
Are you clobberng your Segment register on purpose?
Last edited by mathematician; Sep 14th, 2009 at 4:59 pm.
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Okay then.
Does your assembler understand C defines?
mov sp, 0x7c00
0x7c00 is a C definition.
0x10
Assemblers typically are looking for 07c00h
10h
Does your assembler understand C defines?
mov sp, 0x7c00
0x7c00 is a C definition.
0x10
Assemblers typically are looking for 07c00h
10h
Last edited by wildgoose; Sep 14th, 2009 at 5:10 pm.
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Originally Posted by wildgoose
Okay then.
Does your assembler understand C defines?
mov sp, 0x7c00
0x7c00 is a C definition.
0x10
Assemblers typically are looking for 07c00h
10h
Since I use MASM it recognises 7c00h, but if I used NASM it would recognise 0x7c00.
Last edited by mathematician; Sep 14th, 2009 at 5:14 pm.
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You were using C definitions in the posted code.
Examine your CS register and IP register.
What are their hex values when you first begin the code?
Examine your CS register and IP register.
What are their hex values when you first begin the code?
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As an experiment replace your
with
It'll then force the string load from the code segment!
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Asm Syntax (Toggle Plain Text)
It'll then force the string load from the code segment!
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Originally Posted by wildgoose
You were using C definitions in the posted code.
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Examine your CS register and IP register.
What are their hex values when you first begin the code?
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Everything looks correct but I still think its a Segment:Offset issue.
Initialize your Graphics card Page#0 column 0, row 0. Before doing anything.
And try writing your ASCII letters directly into the text frame buffer.
Initialize your Graphics card Page#0 column 0, row 0. Before doing anything.
And try writing your ASCII letters directly into the text frame buffer.
Assembly Syntax (Toggle Plain Text)
Last edited by wildgoose; Sep 14th, 2009 at 5:30 pm.
It's been a while, but I think this is right.
Upon execution of the bootloader
CS,DS,ES will be zero,
And there is a 512-byte stack allocated by the BIOS.
SS (points where?) SP ?
I do not know if interrupts are disabled.
Has anyone else tested this bootloader?
Could it be because of this guys hardware configuration?
Upon execution of the bootloader
CS,DS,ES will be zero,
And there is a 512-byte stack allocated by the BIOS.
SS (points where?) SP ?
I do not know if interrupts are disabled.
Has anyone else tested this bootloader?
Could it be because of this guys hardware configuration?
----------------------------------------------------------
To control a mind violates a man, and all it has been used for is
hurting and afflicting. Nowonder I progam in assembly...
--->Now available http://dotcoding.netai.net/
To control a mind violates a man, and all it has been used for is
hurting and afflicting. Nowonder I progam in assembly...
--->Now available http://dotcoding.netai.net/
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Originally Posted by NotNull
It's been a while, but I think this is right.
Upon execution of the bootloader
CS,DS,ES will be zero,
And there is a 512-byte stack allocated by the BIOS.
SS (points where?) SP ?
I do not know if interrupts are disabled.
Has anyone else tested this bootloader?
Could it be because of this guys hardware configuration?
It is difficult to see how the hardware configuration can be responsible, assuming that it is running on a PC. The 6845 will have been set up by the bios so that messages like "Not a System Disk" can be displayed.
I haven't got a floppy drive fitted to my computer, so I can't test it.
Last edited by mathematician; Sep 15th, 2009 at 7:48 am.
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