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Line 117... |
| 117 |
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117 |
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| 118 |
/* patch up RMOD's PSP: Parent's PSP segment @ 0x16-0x17 */
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118 |
/* patch up RMOD's PSP: Parent's PSP segment @ 0x16-0x17 */
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| 119 |
myptr[0x16] = rmodseg & 0xff; /* RMOD is his own parent */
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119 |
myptr[0x16] = rmodseg & 0xff; /* RMOD is his own parent */
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| 120 |
myptr[0x17] = rmodseg >> 8;
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120 |
myptr[0x17] = rmodseg >> 8;
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| 121 |
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121 |
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| 122 |
/* patch up RMOD's PSP: SS:SP pointer @ 0x2E-0x31 */
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122 |
/* patch up RMOD's PSP: SS:SP pointer @ 0x2E-0x31 -- I abuse the PSP's
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123 |
* command line tail as stack, but I do NOT set the stacat the end of the
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* tail. E. C. Masloch kindly explained why this would be a bad idea:
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125 |
*
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126 |
* "This is wrong and will potentially overwrite part of your buffers that
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127 |
* start past the PSP. This is because the dword [PSP:2Eh] is not used merely
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128 |
* to set SS:SP but rather to find the stack frame created by the int 21h
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129 |
* call. Therefore the int 21h call that terminates the child process will
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130 |
* then pop a number of registers off starting from the address stored in the
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131 |
* PSP." <https://github.com/SvarDOS/bugz/issues/38#issuecomment-1817445740>
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*/
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| 123 |
myptr[0x2e] = 254; /* I abuse the PSP's command line tail as stack */
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133 |
myptr[0x2e] = 192; /* middle of the command line tail area so I have 64 bytes */
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| 124 |
myptr[0x2f] = 0;
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134 |
myptr[0x2f] = 0; /* before and 64 bytes in front of me */
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| 125 |
myptr[0x30] = rmodseg & 0xff;
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135 |
myptr[0x30] = rmodseg & 0xff;
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| 126 |
myptr[0x31] = rmodseg >> 8;
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136 |
myptr[0x31] = rmodseg >> 8;
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| 127 |
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137 |
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| 128 |
/* patch up RMOD's PSP: JFT size @ 0x32-0x33 */
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138 |
/* patch up RMOD's PSP: JFT size @ 0x32-0x33 */
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| 129 |
myptr[0x32] = 20; /* default JFT size (max that fits without an extra allocation) */
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139 |
myptr[0x32] = 20; /* default JFT size (max that fits without an extra allocation) */
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