115 lines
1.9 KiB
Plaintext
115 lines
1.9 KiB
Plaintext
// lib:
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// print.dsa
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// usage:
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//
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// include print "<relative path>""
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//
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// usage for print:
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// push (register containing address of string)
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// push pcx
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// jmp print::print
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//
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// usage for reset:
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// push pcx
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// jmp print::reset
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//
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// usage for clear:
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// push pcx
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// jmp print::clear
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//
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// usage for print_byte:
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// push (register containing byte)
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// push pcx
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// jmp print::print_byte
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//
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// usage for print_word:
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// push (register containing word)
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// push pcx
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// jmp print::print_word
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//
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dw display: 0x20000
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dw current: 0x20000
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// ------------------------------------------
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// prints the string at addr(arg[0]) to the screen.
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print:
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push bpr
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mov spr, bpr
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ldw bpr, rg0, 8
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ldw current, rg1
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_print_loop:
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ldb rg0, acc
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stb acc, rg1
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addi rg0, 1
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addi rg1, 1
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cmp acc, zero
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jne _print_loop
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jmp _end
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// ------------------------------------------
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// prints the value of arg[0] to the screen.
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print_word:
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// initialise
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push bpr
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mov spr, bpr
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// load byte into acc
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ldw bpr, rg0, 8
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ldw current, rg1
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stw rg0, rg1
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addi rg1, 4
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jmp _end
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// ------------------------------------------
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// prints the last byte of arg[0] to the screen.
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print_byte:
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push bpr
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mov spr, bpr
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ldw bpr, rg0, 8
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ldw current, rg1
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stb rg0, rg1
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addi rg1, 1
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jmp _end
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// ------------------------------------------
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// resets the cursor position on the screen to 0x20000. (0,0)
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reset:
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push bpr
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mov spr, bpr
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ldw display, rg1
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jmp _end
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// ------------------------------------------
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// clears the screen
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clear:
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push bpr
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mov spr, bpr
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// display size = 2000 bytes / 500 words
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lli 500 rg0
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ldw display, rg1
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_clear_loop:
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dec rg0
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stw zero, rg1
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addi rg1, 4
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cmp rg0, zero
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jgt _clear_loop
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jmp _end
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// ------------------------------------------
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// return
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_end:
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stw rg1, current
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mov bpr, spr
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pop bpr
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return |