1 | ; Project name : Assembly Library
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2 | ; Description : Functions for register operations.
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3 |
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4 | ;
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5 | ; XTIDE Universal BIOS and Associated Tools
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6 | ; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2012 by XTIDE Universal BIOS Team.
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7 | ;
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8 | ; This program is free software; you can redistribute it and/or modify
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9 | ; it under the terms of the GNU General Public License as published by
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10 | ; the Free Software Foundation; either version 2 of the License, or
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11 | ; (at your option) any later version.
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12 | ;
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13 | ; This program is distributed in the hope that it will be useful,
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14 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of
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15 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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16 | ; GNU General Public License for more details.
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17 | ; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
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18 | ;
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19 |
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20 | ; Section containing code
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21 | SECTION .text
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22 |
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23 | ;--------------------------------------------------------------------
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24 | ; Registers_ExchangeDSSIwithESDI
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25 | ; Parameters
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26 | ; Nothing
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27 | ; Returns:
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28 | ; DS:SI and ES:DI are exchanged.
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29 | ; Corrupts registers:
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30 | ; Nothing
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31 | ;--------------------------------------------------------------------
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32 | ALIGN JUMP_ALIGN
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33 | Registers_ExchangeDSSIwithESDI:
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34 | push ds
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35 | push es
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36 | pop ds
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37 | pop es
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38 | xchg si, di
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39 | ret
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40 |
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41 |
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42 | ;--------------------------------------------------------------------
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43 | ; Registers_CopySSBPtoESDI
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44 | ; Registers_CopySSBPtoDSSI
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45 | ; Registers_CopyDSSItoESDI
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46 | ; Registers_CopyESDItoDSSI
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47 | ; Parameters
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48 | ; Nothing
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49 | ; Returns:
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50 | ; Copies farm pointer to different segment/pointer register pair
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51 | ; Corrupts registers:
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52 | ; Nothing
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53 | ;--------------------------------------------------------------------
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54 | ALIGN JUMP_ALIGN
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55 | Registers_CopySSBPtoESDI:
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56 | COPY_SSBP_TO_ESDI
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57 | ret
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58 |
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59 | %ifndef EXCLUDE_FROM_XTIDE_UNIVERSAL_BIOS
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60 | ALIGN JUMP_ALIGN
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61 | Registers_CopySSBPtoDSSI:
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62 | COPY_SSBP_TO_DSSI
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63 | ret
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64 |
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65 | ALIGN JUMP_ALIGN
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66 | Registers_CopyDSSItoESDI:
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67 | COPY_DSSI_TO_ESDI
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68 | ret
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69 |
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70 | ALIGN JUMP_ALIGN
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71 | Registers_CopyESDItoDSSI:
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72 | COPY_ESDI_to_DSSI
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73 | ret
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74 | %endif
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75 |
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76 |
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77 | ;--------------------------------------------------------------------
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78 | ; Registers_NormalizeESSI
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79 | ; Registers_NormalizeESDI
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80 | ; Parameters
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81 | ; DS:SI or ES:DI: Ptr to normalize
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82 | ; Returns:
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83 | ; DS:SI or ES:DI: Normalized pointer
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84 | ; Corrupts registers:
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85 | ; AX, CX
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86 | ;
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87 | ; Inline of NORMALIZE_FAR_POINTER so that we can share the last 2/3 of the
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88 | ; routine with Registers_NormalizeFinish.
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89 | ;
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90 | ;--------------------------------------------------------------------
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91 | %ifndef EXCLUDE_FROM_XTIDE_UNIVERSAL_BIOS OR EXCLUDE_FROM_XTIDECFG
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92 | ALIGN JUMP_ALIGN
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93 | Registers_NormalizeESSI:
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94 | mov cx, si
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95 | and si, byte 0fh
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96 | jmp Registers_NormalizeFinish
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97 |
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98 | ALIGN JUMP_ALIGN
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99 | Registers_NormalizeESDI:
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100 | mov cx, di
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101 | and di, byte 0fh
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102 | ;;; fall-through
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103 |
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104 | ALIGN JUMP_ALIGN
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105 | Registers_NormalizeFinish:
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106 | eSHR_IM cx, 4
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107 | mov ax, es
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108 | add ax, cx
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109 | mov es, ax
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110 | ret
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111 | %endif
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112 |
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113 |
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114 | ;--------------------------------------------------------------------
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115 | ; Registers_SetZFifNullPointerInDSSI (commented to save bytes)
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116 | ; Parameters
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117 | ; DS:SI: Far pointer
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118 | ; Returns:
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119 | ; ZF: Set if NULL pointer in DS:SI
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120 | ; Corrupts registers:
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121 | ; Nothing
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122 | ;--------------------------------------------------------------------
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123 | ;ALIGN JUMP_ALIGN
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124 | ;Registers_SetZFifNullPointerInDSSI:
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125 | ; push ax
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126 | ; mov ax, ds
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127 | ; or ax, si
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128 | ; pop ax
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129 | ; ret
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