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| Yet another bootloader https://forum.osdev.org/viewtopic.php?f=1&t=6799 |
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| Author: | Curufir [ Thu Jun 13, 2002 5:05 pm ] |
| Post subject: | Yet another bootloader |
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| Author: | Peter_Vigren [ Thu Jun 13, 2002 5:52 pm ] |
| Post subject: | Re:Yet another bootloader |
First of all I must say that I'm a little impressed that you pushed the adress and then used a RetF to go there... :-) I myself have used a similar way but I haven't seen it implemented anywhere... Second I suggest that you change BIOS_Print to the following: BIOS_Print: Push Ax ; Saving the registers that are changed can be useful Push Bx Mov Bx, 0x0007 ; These are only needed once Mov Ah, 0x0E BIOS_Printing: Lodsb Or Al, Al Jz BIOS_Print_Done Int 0x10 Jmp Short BIOS_Printing BIOS_Print_Done: Push Bx Push Ax RetN I can have done some errors in the code since I'm a bit tired... The rest seems fine to me... I haven't tested it though... and if I should be completely honest I have always used Cmp Ah,0 instead of Or Al,Al... Your way save one byte... Nice... :-) |
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| Author: | Peter_Vigren [ Thu Jun 13, 2002 6:13 pm ] |
| Post subject: | Re:Yet another bootloader |
Peter_Vigren wrote: Cmp Ah,0 instead of Or Al,Al... Your way save one byte... Nice...  Consulting "HelpPC" again I'm seeing that the above isn't true if the register is Ax and if the value compared with is lower than or equal to 8 bits... (If I'm interpreting the information right...) But anyway else it would be true I really should go to sleep now before I write something very odd...
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