flat assembler
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> OS Construction > [solved] Qemu BIOS and Serial |
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revolution 03 Apr 2024, 14:26
Here
Code: read_byte_from_com1: push ax ;... pop ax ret |
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03 Apr 2024, 14:26 |
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jemo07 03 Apr 2024, 17:25
Dohhhhh Thank you!!!... man, was down a rat hole before I got here and just not see that... _________________ Thank you! jemo |
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03 Apr 2024, 17:25 |
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SeproMan 04 Apr 2024, 19:15
@revolution showed you the mistake regarding the serial access.
Additionally there's something wrong in the print_char subroutine. The BIOS.Teletype function always uses the AL register. The masked and/or substituted value in the CL register is never going to be printed! Code: print_char: push ax ; Save the register values push bx mov ah, 0x0E ; BIOS teletype output mov bx, 0x0007 ; Page number and Attribute (light grey on black) and al, 0x7F ; Mask off the high bit (non-ASCII values) cmp al, 0x20 ; Check if the byte is a printable ASCII character jnb .print mov al, '.' ; Print a '.' for non-printable characters .print: int 0x10 ; Call BIOS video interrupt pop bx ; Restore the register values pop ax ret _________________ Real Address Mode. |
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04 Apr 2024, 19:15 |
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