Printing To Screen: Difference between revisions
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→Printing Strings: Added a more advanced C function |
m Reverted edits by Bellezzasolo (talk) to last revision by Solar |
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If you have a pointer to video memory and want to write a string, here is how you might do it; |
If you have a pointer to video memory and want to write a string, here is how you might do it; |
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<pre> |
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<source lang="c"> |
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// note this example will always write to the top |
// note this example will always write to the top |
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// line of the screen |
// line of the screen |
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} |
} |
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} |
} |
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</ |
</pre> |
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This simply cycles through each character in the string, and copies it to the appropriate place in video memory. |
This simply cycles through each character in the string, and copies it to the appropriate place in video memory. |
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Here is a more advanced set of functions (C code compatible with C++): |
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<source lang="c"> |
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//User:bellezzasolo: excerpt from my OS. In my OS this is C++ |
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//This will work in both C and C++ |
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//MODE 3 printing text |
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#include "stdio.h" //Put definitons of these functions here |
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#define UCHAR unsigned char |
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int x = 0; |
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int y = 0; |
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unsigned short* vidmem = (unsigned short*)0xb8000; |
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UCHAR color = (UCHAR)0x3f; //Avoid compiler error. This produces white on light blue. You can change this if you want |
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void setColor(UCHAR foreground, UCHAR background) |
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{ |
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color = (background<<4 | foreground); |
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} |
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void putc(char c) //Prints a character |
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{ |
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unsigned short temp = (unsigned short)((color << 8)|c); |
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unsigned short* vid = (unsigned short*)(vidmem + y*80 +x); |
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*vid = c; |
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x++; |
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if(x>80) |
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{ |
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y++; |
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x=0; |
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if(y>25) |
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{ |
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scroll(); |
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} |
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} |
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} |
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void Puts(char* string) |
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{ |
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if(!string) |
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return; |
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char* stream = string; |
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while(*stream != 0) |
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{ |
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putc(*stream); |
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stream++; |
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} |
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} |
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</source> |
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==Printing Integers== |
==Printing Integers== |
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