| 1 | ; Project name : Assembly Library |
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| 2 | ; Description : Functions for outputting characters to video memory. |
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| 3 | ; These functions are meant to be called by Display_CharacterFromAL |
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| 4 | ; and Display_RepeatCharacterFromAL using function pointer |
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| 5 | ; stored in DISPLAY_CONTEXT. |
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| 6 | |
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| 7 | ; Section containing code |
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| 8 | SECTION .text |
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| 9 | |
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| 10 | ;-------------------------------------------------------------------- |
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| 11 | ; DisplayCharOut_TeletypeOutputWithAttribute |
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| 12 | ; DisplayCharOut_TeletypeOutput |
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| 13 | ; Parameters: |
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| 14 | ; AL: Character to output |
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| 15 | ; AH: Attribute to output |
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| 16 | ; DS: BDA segment (zero) |
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| 17 | ; ES:DI: Ptr to video memory where to output |
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| 18 | ; Returns: |
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| 19 | ; DI: Incremented for next character |
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| 20 | ; Corrupts registers: |
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| 21 | ; AX, DX |
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| 22 | ;-------------------------------------------------------------------- |
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| 23 | ALIGN JUMP_ALIGN |
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| 24 | DisplayCharOut_TeletypeOutputWithAttribute: |
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| 25 | cmp al, ' ' ; Printable character? |
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| 26 | jb SHORT DisplayCharOut_BiosTeletypeOutput |
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| 27 | WAIT_RETRACE_IF_NECESSARY_THEN stosw |
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| 28 | ret |
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| 29 | |
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| 30 | ALIGN JUMP_ALIGN |
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| 31 | DisplayCharOut_TeletypeOutput: |
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| 32 | cmp al, ' ' ; Printable character? |
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| 33 | jae SHORT DisplayCharOut_Character |
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| 34 | ; Fall to DisplayCharOut_BiosTeletypeOutput |
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| 35 | |
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| 36 | ;-------------------------------------------------------------------- |
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| 37 | ; DisplayCharOut_BiosTeletypeOutput |
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| 38 | ; Parameters: |
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| 39 | ; AL: Control character |
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| 40 | ; DS: BDA segment (zero) |
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| 41 | ; ES:DI: Ptr to video memory where to output |
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| 42 | ; Returns: |
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| 43 | ; DI: Incremented for next character |
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| 44 | ; Corrupts registers: |
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| 45 | ; AX, DX |
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| 46 | ;-------------------------------------------------------------------- |
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| 47 | ALIGN JUMP_ALIGN |
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| 48 | DisplayCharOut_BiosTeletypeOutput: |
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| 49 | push ax |
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| 50 | call DisplayCursor_SynchronizeCoordinatesToHardware |
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| 51 | pop ax |
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| 52 | |
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| 53 | ; Output character with BIOS |
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| 54 | push bx |
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| 55 | mov ah, TELETYPE_OUTPUT |
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| 56 | mov bh, [VIDEO_BDA.bActivePage] |
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| 57 | int BIOS_VIDEO_INTERRUPT_10h |
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| 58 | pop bx |
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| 59 | |
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| 60 | call DisplayCursor_GetHardwareCoordinatesToAX |
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| 61 | jmp DisplayCursor_SetCoordinatesFromAX |
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| 62 | |
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| 63 | |
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| 64 | ;-------------------------------------------------------------------- |
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| 65 | ; DisplayCharOut_Attribute |
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| 66 | ; DisplayCharOut_Character |
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| 67 | ; DisplayCharOut_CharacterWithAttribute |
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| 68 | ; Parameters: |
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| 69 | ; AL: Character to output |
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| 70 | ; AH: Attribute to output |
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| 71 | ; DS: BDA segment (zero) |
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| 72 | ; ES:DI: Ptr to video memory where to output |
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| 73 | ; Returns: |
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| 74 | ; DI: Incremented for next character |
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| 75 | ; Corrupts registers: |
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| 76 | ; AX, DX |
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| 77 | ;-------------------------------------------------------------------- |
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| 78 | ALIGN JUMP_ALIGN |
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| 79 | DisplayCharOut_Attribute: |
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| 80 | xchg al, ah ; Swap character and attribute |
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| 81 | inc di ; Skip character |
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| 82 | WAIT_RETRACE_IF_NECESSARY_THEN stosb |
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| 83 | ret |
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| 84 | |
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| 85 | ALIGN JUMP_ALIGN |
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| 86 | DisplayCharOut_Character: |
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| 87 | WAIT_RETRACE_IF_NECESSARY_THEN stosb |
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| 88 | inc di ; Skip attribute |
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| 89 | ret |
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| 90 | |
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| 91 | ALIGN JUMP_ALIGN |
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| 92 | DisplayCharOut_CharacterWithAttribute: |
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| 93 | WAIT_RETRACE_IF_NECESSARY_THEN stosw |
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| 94 | ret |
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| 95 | |
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| 96 | |
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| 97 | ;-------------------------------------------------------------------- |
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| 98 | ; DisplayCharOut_WriteCharacterToBuffer |
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| 99 | ; Parameters: |
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| 100 | ; AL: Character to output |
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| 101 | ; DS: BDA segment (zero) |
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| 102 | ; ES:DI: Ptr to destination string buffer |
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| 103 | ; DISPLAY_CONTEXT.wCharOutParam: Characters left in buffer |
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| 104 | ; Returns: |
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| 105 | ; ES:DI: Updated for next character |
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| 106 | ; Corrupts registers: |
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| 107 | ; AX, DX |
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| 108 | ;-------------------------------------------------------------------- |
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| 109 | ALIGN JUMP_ALIGN |
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| 110 | DisplayCharOut_WriteCharacterToBuffer: |
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| 111 | cmp WORD [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.wCharOutParam], BYTE 0 |
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| 112 | je SHORT .BufferFull |
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| 113 | stosb |
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| 114 | dec WORD [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.wCharOutParam] |
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| 115 | .BufferFull: |
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| 116 | ret |
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