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ReturnInfinity / BareMetal-OS-legacy

BareMetal is a 64-bit OS for x86-64 based computers. The OS is written entirely in Assembly while applications can be written in Assembly, C/C++, and Rust.
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os_output_char in Kernel API #94

Closed Roxxik closed 9 years ago

Roxxik commented 9 years ago

There is currently no way to just put one character on screen. To prepare the new syscall we need to be able to output an arbitary char first. The current output functions only allow to output a printable char or space or a whole string

For that i recommend a few changes to the screen.asm

rename os_output_char to os_output_printable create new function os_output_char change os_output_chars to repeatedly call os_output_char

the interface of os_output_char is the same as the interface of os_output_printable os_output_char either prints newline/tab or calls os_output_printable

after this has been done the os_output_char could be part of the Kernel API.

ohnx commented 9 years ago

I believe this has changed in the other version of BareMetal OS here.

Roxxik commented 9 years ago

Haven't seen that yet, why are there two versions of the OS?

Roxxik commented 9 years ago

eventhough in the other repo is no syscall that can output a newline directly

IanSeyler commented 9 years ago

os_output_chars is able to print a single character. In needs the address of where the character is in memory and a count value of 1.

To print a newline you can use this:

mov rsi, newline mov rcx, 1 call os_output_chars ... newline: db 13, 0

Roxxik commented 9 years ago

i'd do this like char c = '\n'; b_output_chars(&c,1);