[41] | 1 | ; File name : DisplayCharOut.asm |
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| 2 | ; Project name : Assembly Library |
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| 3 | ; Created date : 26.6.2010 |
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[42] | 4 | ; Last update : 18.9.2010 |
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[41] | 5 | ; Author : Tomi Tilli |
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| 6 | ; Description : Functions for outputting characters to video memory. |
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| 7 | ; These functions are meant to be called by Display_CharacterFromAL |
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| 8 | ; and Display_RepeatCharacterFromAL using function pointer |
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| 9 | ; stored in DISPLAY_CONTEXT. |
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| 10 | |
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| 11 | ; Section containing code |
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| 12 | SECTION .text |
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| 13 | |
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| 14 | ;-------------------------------------------------------------------- |
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[42] | 15 | ; WAIT_RETRACE_IF_NECESSARY_THEN |
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| 16 | ; Parameters: |
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| 17 | ; AL: Character to output |
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| 18 | ; AH: Attribute to output (stosw only) |
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| 19 | ; DS: BDA segment (zero) |
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| 20 | ; ES:DI: Ptr to video memory where to output |
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| 21 | ; Returns: |
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| 22 | ; DI: Incremented for next character |
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| 23 | ; Corrupts registers: |
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| 24 | ; AX, DX |
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| 25 | ;-------------------------------------------------------------------- |
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| 26 | %macro WAIT_RETRACE_IF_NECESSARY_THEN 1 |
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| 27 | %ifdef ELIMINATE_CGA_SNOW |
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| 28 | %ifidn %1, stosb |
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| 29 | call StosbWithoutCgaSnow |
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| 30 | %else |
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| 31 | call StoswWithoutCgaSnow |
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| 32 | %endif |
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| 33 | %else |
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| 34 | %1 ; STOSB or STOSW |
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| 35 | %endif |
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| 36 | %endmacro |
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| 37 | |
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| 38 | |
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| 39 | ;-------------------------------------------------------------------- |
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[41] | 40 | ; DisplayCharOut_TeletypeOutputWithAttribute |
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| 41 | ; DisplayCharOut_TeletypeOutput |
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| 42 | ; Parameters: |
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| 43 | ; AL: Character to output |
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| 44 | ; AH: Attribute to output |
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| 45 | ; DS: BDA segment (zero) |
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| 46 | ; ES:DI: Ptr to video memory where to output |
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| 47 | ; Returns: |
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| 48 | ; DI: Incremented for next character |
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| 49 | ; Corrupts registers: |
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| 50 | ; AX, DX |
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| 51 | ;-------------------------------------------------------------------- |
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| 52 | ALIGN JUMP_ALIGN |
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| 53 | DisplayCharOut_TeletypeOutputWithAttribute: |
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| 54 | cmp al, ' ' ; Printable character? |
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| 55 | jb SHORT DisplayCharOut_BiosTeletypeOutput |
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[42] | 56 | WAIT_RETRACE_IF_NECESSARY_THEN stosw |
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[41] | 57 | ret |
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| 58 | |
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| 59 | ALIGN JUMP_ALIGN |
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| 60 | DisplayCharOut_TeletypeOutput: |
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| 61 | cmp al, ' ' ; Printable character? |
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| 62 | jae SHORT DisplayCharOut_Character |
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| 63 | ; Fall to DisplayCharOut_BiosTeletypeOutput |
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| 64 | |
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| 65 | ;-------------------------------------------------------------------- |
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| 66 | ; DisplayCharOut_BiosTeletypeOutput |
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| 67 | ; Parameters: |
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| 68 | ; AL: Control character |
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| 69 | ; DS: BDA segment (zero) |
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| 70 | ; ES:DI: Ptr to video memory where to output |
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| 71 | ; Returns: |
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| 72 | ; DI: Incremented for next character |
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| 73 | ; Corrupts registers: |
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| 74 | ; AX, DX |
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| 75 | ;-------------------------------------------------------------------- |
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| 76 | ALIGN JUMP_ALIGN |
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| 77 | DisplayCharOut_BiosTeletypeOutput: |
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| 78 | push ax |
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| 79 | call DisplayCursor_SynchronizeCoordinatesToHardware |
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| 80 | pop ax |
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| 81 | call .OutputCharacterWithBIOS |
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| 82 | call DisplayCursor_GetHardwareCoordinatesToAX |
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| 83 | jmp DisplayCursor_SetCoordinatesFromAX |
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| 84 | |
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| 85 | ;-------------------------------------------------------------------- |
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| 86 | ; .OutputCharacterWithBIOS |
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| 87 | ; Parameters: |
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| 88 | ; AL: Character to output |
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| 89 | ; DS: BDA segment |
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| 90 | ; Returns: |
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| 91 | ; Nothing |
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| 92 | ; Corrupts registers: |
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| 93 | ; AX |
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| 94 | ;-------------------------------------------------------------------- |
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| 95 | ALIGN JUMP_ALIGN |
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| 96 | .OutputCharacterWithBIOS: |
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| 97 | push bx |
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| 98 | mov ah, TELETYPE_OUTPUT |
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| 99 | mov bh, [VIDEO_BDA.bActivePage] |
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| 100 | int BIOS_VIDEO_INTERRUPT_10h |
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| 101 | pop bx |
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| 102 | ret |
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| 103 | |
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| 104 | |
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| 105 | ;-------------------------------------------------------------------- |
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| 106 | ; DisplayCharOut_Attribute |
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| 107 | ; DisplayCharOut_Character |
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| 108 | ; DisplayCharOut_CharacterWithAttribute |
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| 109 | ; Parameters: |
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| 110 | ; AL: Character to output |
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| 111 | ; AH: Attribute to output |
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[42] | 112 | ; DS: BDA segment (zero) |
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[41] | 113 | ; ES:DI: Ptr to video memory where to output |
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| 114 | ; Returns: |
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| 115 | ; DI: Incremented for next character |
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| 116 | ; Corrupts registers: |
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[42] | 117 | ; AX, DX |
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[41] | 118 | ;-------------------------------------------------------------------- |
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| 119 | ALIGN JUMP_ALIGN |
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| 120 | DisplayCharOut_Attribute: |
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| 121 | xchg al, ah ; Swap character and attribute |
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| 122 | inc di ; Skip character |
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[42] | 123 | WAIT_RETRACE_IF_NECESSARY_THEN stosb |
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[41] | 124 | ret |
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| 125 | |
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| 126 | ALIGN JUMP_ALIGN |
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| 127 | DisplayCharOut_Character: |
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[42] | 128 | WAIT_RETRACE_IF_NECESSARY_THEN stosb |
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[41] | 129 | inc di ; Skip attribute |
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| 130 | ret |
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| 131 | |
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| 132 | ALIGN JUMP_ALIGN |
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| 133 | DisplayCharOut_CharacterWithAttribute: |
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[42] | 134 | WAIT_RETRACE_IF_NECESSARY_THEN stosw |
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[41] | 135 | ret |
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| 136 | |
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| 137 | |
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| 138 | ;-------------------------------------------------------------------- |
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| 139 | ; DisplayCharOut_WriteCharacterToBuffer |
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| 140 | ; Parameters: |
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| 141 | ; AL: Character to output |
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| 142 | ; DS: BDA segment (zero) |
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| 143 | ; ES:DI: Ptr to destination string buffer |
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| 144 | ; DISPLAY_CONTEXT.wCharOutParam: Offset to end of buffer (one past last) |
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| 145 | ; Returns: |
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| 146 | ; ES:DI: Updated for next character |
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| 147 | ; Corrupts registers: |
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| 148 | ; AX, DX |
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| 149 | ;-------------------------------------------------------------------- |
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| 150 | ALIGN JUMP_ALIGN |
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| 151 | DisplayCharOut_WriteCharacterToBuffer: |
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| 152 | cmp di, [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.wCharOutParam] |
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| 153 | jae SHORT .BufferFull |
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| 154 | stosb |
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| 155 | .BufferFull: |
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| 156 | ret |
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[42] | 157 | |
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| 158 | |
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| 159 | ; STOSB and STOSW replacement functions to prevent CGA snow. These will slow |
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| 160 | ; drawing a lot so use them only if it is necessary to eliminate CGA snow. |
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| 161 | %ifdef ELIMINATE_CGA_SNOW |
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| 162 | |
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| 163 | OFFSET_TO_CGA_STATUS_REGISTER EQU 6 ; Base port 3D4h + 6 = 3DAh |
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| 164 | CGA_STATUS_REGISTER EQU 3DAh |
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| 165 | |
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| 166 | ;-------------------------------------------------------------------- |
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| 167 | ; WAIT_UNTIL_SAFE_CGA_WRITE |
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| 168 | ; Parameters: |
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| 169 | ; DX: CGA Status Register Address (3DAh) |
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| 170 | ; Returns: |
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| 171 | ; Interrupts disabled |
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| 172 | ; Corrupts registers: |
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| 173 | ; AL |
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| 174 | ;-------------------------------------------------------------------- |
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| 175 | %macro WAIT_UNTIL_SAFE_CGA_WRITE 0 |
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| 176 | cli ; Interrupt request would mess up timing |
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| 177 | %%WaitUntilNotInRetrace: |
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| 178 | in al, dx |
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| 179 | shr al, 1 ; 1 = Bit 0: A 1 indicates that regen-buffer memory access can be |
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| 180 | ; made without interfering with the display. (H or V retrace) |
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| 181 | jc SHORT %%WaitUntilNotInRetrace |
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| 182 | sti |
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| 183 | nop ; Should have time to serve IRQ here |
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| 184 | cli |
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| 185 | %%WaitUntilNextRetraceStarts: |
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| 186 | in al, dx |
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| 187 | shr al, 1 |
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| 188 | jnc SHORT %%WaitUntilNextRetraceStarts |
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| 189 | %endmacro |
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| 190 | |
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| 191 | ;-------------------------------------------------------------------- |
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| 192 | ; StosbWithoutCgaSnow |
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| 193 | ; StoswWithoutCgaSnow |
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| 194 | ; Parameters: |
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| 195 | ; AL: Character to output |
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| 196 | ; AH: Attribute to output (StoswWithoutCgaSnow only) |
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| 197 | ; DS: BDA segment (zero) |
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| 198 | ; ES:DI: Ptr to video memory where to output |
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| 199 | ; Returns: |
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| 200 | ; DI: Incremented for next character |
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| 201 | ; Corrupts registers: |
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| 202 | ; AX, DX |
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| 203 | ;-------------------------------------------------------------------- |
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| 204 | ALIGN JUMP_ALIGN |
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| 205 | StosbWithoutCgaSnow: |
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| 206 | call LoadAndVerifyStatusRegisterFromBDA |
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| 207 | jne SHORT .StosbWithoutWaitSinceUnknownPort |
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| 208 | |
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| 209 | mov ah, al |
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| 210 | WAIT_UNTIL_SAFE_CGA_WRITE |
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| 211 | mov al, ah |
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| 212 | stosb |
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| 213 | sti |
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| 214 | ret |
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| 215 | ALIGN JUMP_ALIGN |
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| 216 | .StosbWithoutWaitSinceUnknownPort: |
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| 217 | stosb |
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| 218 | ret |
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| 219 | |
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| 220 | ALIGN JUMP_ALIGN |
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| 221 | StoswWithoutCgaSnow: |
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| 222 | call LoadAndVerifyStatusRegisterFromBDA |
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| 223 | jne SHORT .StoswWithoutWaitSinceUnknownPort |
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| 224 | |
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| 225 | push bx |
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| 226 | xchg bx, ax |
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| 227 | WAIT_UNTIL_SAFE_CGA_WRITE |
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| 228 | xchg ax, bx |
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| 229 | stosw |
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| 230 | pop bx |
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| 231 | sti |
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| 232 | ret |
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| 233 | ALIGN JUMP_ALIGN |
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| 234 | .StoswWithoutWaitSinceUnknownPort: |
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| 235 | stosw |
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| 236 | ret |
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| 237 | |
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| 238 | ;-------------------------------------------------------------------- |
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| 239 | ; LoadAndVerifyStatusRegisterFromBDA |
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| 240 | ; Parameters: |
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| 241 | ; DS: BDA segment (zero) |
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| 242 | ; Returns: |
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| 243 | ; DX: CGA Status Register Address |
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| 244 | ; ZF: Set if CGA Base Port found in BDA |
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| 245 | ; Corrupts registers: |
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| 246 | ; Nothing |
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| 247 | ;-------------------------------------------------------------------- |
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| 248 | ALIGN JUMP_ALIGN |
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| 249 | LoadAndVerifyStatusRegisterFromBDA: |
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| 250 | mov dx, [BDA.wVidPort] |
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| 251 | add dl, OFFSET_TO_CGA_STATUS_REGISTER |
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| 252 | cmp dx, CGA_STATUS_REGISTER |
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| 253 | ret |
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| 254 | |
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| 255 | %endif ; ELIMINATE_CGA_SNOW |
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