1 | // |
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2 | // x_store.sa 3.2 1/24/91 |
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3 | // |
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4 | // store --- store operand to memory or register |
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5 | // |
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6 | // Used by underflow and overflow handlers. |
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7 | // |
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8 | // a6 = points to fp value to be stored. |
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9 | // |
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10 | |
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11 | // Copyright (C) Motorola, Inc. 1990 |
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12 | // All Rights Reserved |
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13 | // |
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14 | // THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA |
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15 | // The copyright notice above does not evidence any |
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16 | // actual or intended publication of such source code. |
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17 | |
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18 | X_STORE: //idnt 2,1 | Motorola 040 Floating Point Software Package |
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19 | |
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20 | |section 8 |
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21 | |
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22 | fpreg_mask: |
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23 | .byte 0x80,0x40,0x20,0x10,0x08,0x04,0x02,0x01 |
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24 | |
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25 | .include "fpsp.defs" |
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26 | |
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27 | |xref mem_write |
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28 | |xref get_fline |
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29 | |xref g_opcls |
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30 | |xref g_dfmtou |
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31 | |xref reg_dest |
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32 | |
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33 | .global dest_ext |
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34 | .global dest_dbl |
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35 | .global dest_sgl |
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36 | |
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37 | .global store |
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38 | store: |
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39 | btstb #E3,E_BYTE(%a6) |
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40 | beqs E1_sto |
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41 | E3_sto: |
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42 | movel CMDREG3B(%a6),%d0 |
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43 | bfextu %d0{#6:#3},%d0 //isolate dest. reg from cmdreg3b |
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44 | sto_fp: |
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45 | lea fpreg_mask,%a1 |
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46 | moveb (%a1,%d0.w),%d0 //convert reg# to dynamic register mask |
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47 | tstb LOCAL_SGN(%a0) |
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48 | beqs is_pos |
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49 | bsetb #sign_bit,LOCAL_EX(%a0) |
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50 | is_pos: |
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51 | fmovemx (%a0),%d0 //move to correct register |
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52 | // |
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53 | // if fp0-fp3 is being modified, we must put a copy |
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54 | // in the USER_FPn variable on the stack because all exception |
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55 | // handlers restore fp0-fp3 from there. |
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56 | // |
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57 | cmpb #0x80,%d0 |
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58 | bnes not_fp0 |
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59 | fmovemx %fp0-%fp0,USER_FP0(%a6) |
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60 | rts |
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61 | not_fp0: |
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62 | cmpb #0x40,%d0 |
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63 | bnes not_fp1 |
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64 | fmovemx %fp1-%fp1,USER_FP1(%a6) |
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65 | rts |
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66 | not_fp1: |
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67 | cmpb #0x20,%d0 |
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68 | bnes not_fp2 |
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69 | fmovemx %fp2-%fp2,USER_FP2(%a6) |
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70 | rts |
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71 | not_fp2: |
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72 | cmpb #0x10,%d0 |
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73 | bnes not_fp3 |
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74 | fmovemx %fp3-%fp3,USER_FP3(%a6) |
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75 | rts |
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76 | not_fp3: |
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77 | rts |
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78 | |
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79 | E1_sto: |
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80 | bsrl g_opcls //returns opclass in d0 |
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81 | cmpib #3,%d0 |
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82 | beq opc011 //branch if opclass 3 |
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83 | movel CMDREG1B(%a6),%d0 |
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84 | bfextu %d0{#6:#3},%d0 //extract destination register |
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85 | bras sto_fp |
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86 | |
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87 | opc011: |
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88 | bsrl g_dfmtou //returns dest format in d0 |
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89 | // ;ext=00, sgl=01, dbl=10 |
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90 | movel %a0,%a1 //save source addr in a1 |
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91 | movel EXC_EA(%a6),%a0 //get the address |
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92 | cmpil #0,%d0 //if dest format is extended |
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93 | beq dest_ext //then branch |
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94 | cmpil #1,%d0 //if dest format is single |
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95 | beqs dest_sgl //then branch |
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96 | // |
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97 | // fall through to dest_dbl |
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98 | // |
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99 | |
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100 | // |
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101 | // dest_dbl --- write double precision value to user space |
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102 | // |
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103 | //Input |
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104 | // a0 -> destination address |
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105 | // a1 -> source in extended precision |
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106 | //Output |
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107 | // a0 -> destroyed |
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108 | // a1 -> destroyed |
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109 | // d0 -> 0 |
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110 | // |
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111 | //Changes extended precision to double precision. |
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112 | // Note: no attempt is made to round the extended value to double. |
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113 | // dbl_sign = ext_sign |
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114 | // dbl_exp = ext_exp - $3fff(ext bias) + $7ff(dbl bias) |
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115 | // get rid of ext integer bit |
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116 | // dbl_mant = ext_mant{62:12} |
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117 | // |
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118 | // --------------- --------------- --------------- |
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119 | // extended -> |s| exp | |1| ms mant | | ls mant | |
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120 | // --------------- --------------- --------------- |
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121 | // 95 64 63 62 32 31 11 0 |
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122 | // | | |
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123 | // | | |
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124 | // | | |
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125 | // v v |
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126 | // --------------- --------------- |
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127 | // double -> |s|exp| mant | | mant | |
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128 | // --------------- --------------- |
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129 | // 63 51 32 31 0 |
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130 | // |
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131 | dest_dbl: |
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132 | clrl %d0 //clear d0 |
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133 | movew LOCAL_EX(%a1),%d0 //get exponent |
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134 | subw #0x3fff,%d0 //subtract extended precision bias |
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135 | cmpw #0x4000,%d0 //check if inf |
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136 | beqs inf //if so, special case |
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137 | addw #0x3ff,%d0 //add double precision bias |
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138 | swap %d0 //d0 now in upper word |
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139 | lsll #4,%d0 //d0 now in proper place for dbl prec exp |
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140 | tstb LOCAL_SGN(%a1) |
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141 | beqs get_mant //if positive, go process mantissa |
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142 | bsetl #31,%d0 //if negative, put in sign information |
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143 | // ; before continuing |
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144 | bras get_mant //go process mantissa |
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145 | inf: |
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146 | movel #0x7ff00000,%d0 //load dbl inf exponent |
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147 | clrl LOCAL_HI(%a1) //clear msb |
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148 | tstb LOCAL_SGN(%a1) |
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149 | beqs dbl_inf //if positive, go ahead and write it |
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150 | bsetl #31,%d0 //if negative put in sign information |
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151 | dbl_inf: |
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152 | movel %d0,LOCAL_EX(%a1) //put the new exp back on the stack |
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153 | bras dbl_wrt |
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154 | get_mant: |
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155 | movel LOCAL_HI(%a1),%d1 //get ms mantissa |
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156 | bfextu %d1{#1:#20},%d1 //get upper 20 bits of ms |
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157 | orl %d1,%d0 //put these bits in ms word of double |
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158 | movel %d0,LOCAL_EX(%a1) //put the new exp back on the stack |
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159 | movel LOCAL_HI(%a1),%d1 //get ms mantissa |
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160 | movel #21,%d0 //load shift count |
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161 | lsll %d0,%d1 //put lower 11 bits in upper bits |
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162 | movel %d1,LOCAL_HI(%a1) //build lower lword in memory |
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163 | movel LOCAL_LO(%a1),%d1 //get ls mantissa |
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164 | bfextu %d1{#0:#21},%d0 //get ls 21 bits of double |
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165 | orl %d0,LOCAL_HI(%a1) //put them in double result |
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166 | dbl_wrt: |
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167 | movel #0x8,%d0 //byte count for double precision number |
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168 | exg %a0,%a1 //a0=supervisor source, a1=user dest |
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169 | bsrl mem_write //move the number to the user's memory |
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170 | rts |
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171 | // |
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172 | // dest_sgl --- write single precision value to user space |
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173 | // |
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174 | //Input |
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175 | // a0 -> destination address |
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176 | // a1 -> source in extended precision |
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177 | // |
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178 | //Output |
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179 | // a0 -> destroyed |
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180 | // a1 -> destroyed |
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181 | // d0 -> 0 |
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182 | // |
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183 | //Changes extended precision to single precision. |
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184 | // sgl_sign = ext_sign |
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185 | // sgl_exp = ext_exp - $3fff(ext bias) + $7f(sgl bias) |
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186 | // get rid of ext integer bit |
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187 | // sgl_mant = ext_mant{62:12} |
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188 | // |
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189 | // --------------- --------------- --------------- |
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190 | // extended -> |s| exp | |1| ms mant | | ls mant | |
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191 | // --------------- --------------- --------------- |
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192 | // 95 64 63 62 40 32 31 12 0 |
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193 | // | | |
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194 | // | | |
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195 | // | | |
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196 | // v v |
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197 | // --------------- |
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198 | // single -> |s|exp| mant | |
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199 | // --------------- |
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200 | // 31 22 0 |
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201 | // |
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202 | dest_sgl: |
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203 | clrl %d0 |
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204 | movew LOCAL_EX(%a1),%d0 //get exponent |
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205 | subw #0x3fff,%d0 //subtract extended precision bias |
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206 | cmpw #0x4000,%d0 //check if inf |
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207 | beqs sinf //if so, special case |
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208 | addw #0x7f,%d0 //add single precision bias |
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209 | swap %d0 //put exp in upper word of d0 |
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210 | lsll #7,%d0 //shift it into single exp bits |
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211 | tstb LOCAL_SGN(%a1) |
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212 | beqs get_sman //if positive, continue |
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213 | bsetl #31,%d0 //if negative, put in sign first |
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214 | bras get_sman //get mantissa |
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215 | sinf: |
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216 | movel #0x7f800000,%d0 //load single inf exp to d0 |
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217 | tstb LOCAL_SGN(%a1) |
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218 | beqs sgl_wrt //if positive, continue |
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219 | bsetl #31,%d0 //if negative, put in sign info |
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220 | bras sgl_wrt |
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221 | |
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222 | get_sman: |
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223 | movel LOCAL_HI(%a1),%d1 //get ms mantissa |
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224 | bfextu %d1{#1:#23},%d1 //get upper 23 bits of ms |
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225 | orl %d1,%d0 //put these bits in ms word of single |
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226 | |
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227 | sgl_wrt: |
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228 | movel %d0,L_SCR1(%a6) //put the new exp back on the stack |
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229 | movel #0x4,%d0 //byte count for single precision number |
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230 | tstl %a0 //users destination address |
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231 | beqs sgl_Dn //destination is a data register |
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232 | exg %a0,%a1 //a0=supervisor source, a1=user dest |
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233 | leal L_SCR1(%a6),%a0 //point a0 to data |
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234 | bsrl mem_write //move the number to the user's memory |
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235 | rts |
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236 | sgl_Dn: |
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237 | bsrl get_fline //returns fline word in d0 |
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238 | andw #0x7,%d0 //isolate register number |
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239 | movel %d0,%d1 //d1 has size:reg formatted for reg_dest |
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240 | orl #0x10,%d1 //reg_dest wants size added to reg# |
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241 | bral reg_dest //size is X, rts in reg_dest will |
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242 | // ;return to caller of dest_sgl |
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243 | |
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244 | dest_ext: |
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245 | tstb LOCAL_SGN(%a1) //put back sign into exponent word |
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246 | beqs dstx_cont |
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247 | bsetb #sign_bit,LOCAL_EX(%a1) |
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248 | dstx_cont: |
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249 | clrb LOCAL_SGN(%a1) //clear out the sign byte |
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250 | |
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251 | movel #0x0c,%d0 //byte count for extended number |
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252 | exg %a0,%a1 //a0=supervisor source, a1=user dest |
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253 | bsrl mem_write //move the number to the user's memory |
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254 | rts |
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255 | |
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256 | |end |
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