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pascal@13691
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1 #include <stdio.h>
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pascal@13691
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2 #include "iso9660.h"
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pascal@13691
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3
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pascal@13691
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4 static unsigned version;
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pascal@13691
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5 #define SETUPSECTORS 0x1F1
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pascal@13691
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6 #define ROFLAG 0x1F2
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pascal@13691
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7 #define SYSSIZE 0x1F4
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pascal@13691
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8 #define VIDEOMODE 0x1FA
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pascal@13691
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9 #define BOOTFLAG 0x1FE
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pascal@13691
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10 #define HEADER 0x202
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pascal@13691
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11 #define VERSION 0x206
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pascal@13691
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12 #define RMSWOFS 0x208
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pascal@13691
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13 #define RMSWSEG 0x20A
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pascal@13691
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14 #define LOADERTYPE 0x210
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pascal@13691
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15 #define LOADFLAGS 0x211
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16 #define SYSTEMCODE 0x214
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pascal@13691
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17 #define INITRDCODE 0x218
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pascal@13691
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18 #define INITRDSIZE 0x21C
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pascal@13691
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19 #define HEAPPTR 0x224
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pascal@13691
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20 #define CMDLINE 0x228
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21
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pascal@13691
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22 #define SETUP_SEGMENT 0x9000
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pascal@13691
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23 #define CMDLINE_OFFSET 0x9E00
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24
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pascal@13691
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25 #define BUFFERSZ 2*1024
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26 static char buffer[BUFFERSZ];
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27 static unsigned long initrd_addr, initrd_size;
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28
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pascal@13691
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29 static int may_exit_dos = 1;
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pascal@13691
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30 static void die(char *msg)
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31 {
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32 printf("%s.\n", msg);
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pascal@13691
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33 if (may_exit_dos)
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34 exit(1);
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pascal@13691
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35 while (1);
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pascal@13691
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36 }
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37
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pascal@13691
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38 static int vm86(void)
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39 {
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pascal@13691
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40 #asm
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pascal@13691
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41 smsw ax
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pascal@13691
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42 and ax, #1 // 0:realmode 1:vm86
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43 #endasm
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44 }
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45
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46 static struct mem {
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47 unsigned long base;
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pascal@13691
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48 int align;
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pascal@13691
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49 } kernelmem = { 0x100000, 0 };
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50
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pascal@13691
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51 #define initrdmem kernelmem
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52
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pascal@13691
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53 static void movehi(void)
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54 {
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pascal@13691
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55 #asm
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pascal@13691
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56 pusha
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pascal@13691
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57 xor di, di // 30
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58 mov cx, #9 // 2E..1E
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59 zero1:
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60 push di
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61 loop zero1
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62 push dword [_kernelmem] // 1A p->base
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63 push #-1 // 18
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64 push di // 16
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65 xor eax, eax
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66 cdq
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67 mov dx, ds
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68 shl edx, #4
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69 mov ax, #_buffer
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70 add edx, eax
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71 push edx // 12 linear_address(buffer)
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72 push #-1 // 10
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pascal@13691
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73 mov cl, #8 // 0E..00
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74 zero2:
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75 push di
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pascal@13691
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76 loop zero2
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pascal@13691
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77 mov ch, #BUFFERSZ/512
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78 push ss
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79 pop es
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pascal@13691
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80 mov si, sp
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pascal@13691
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81 mov ax, #0x8793
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82 mov [si+0x15], al
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83 xchg [si+0x1D], al
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pascal@13691
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84 mov [si+0x1F], al // bits 24..31, doesn't work for me :(
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pascal@13691
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85 int 0x15
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86 add sp, #0x30
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87 popa
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pascal@13691
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88 #endasm
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pascal@13691
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89 }
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90
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pascal@13691
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91 static void load(struct mem *p, unsigned long size)
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92 {
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93 if (vm86())
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94 die("Need real mode");
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pascal@13691
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95 switch (p->align) {
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96 case 0: // kernel
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97 p->align = 4096;
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98 break;
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99 case 4096: // first initrd
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100 initrd_addr = p->base;
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101 p->align = 4;
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102 }
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pascal@13691
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103 while (size) {
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104 int n, s = sizeof(buffer);
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105 for (n = 0; n < s; n++) buffer[n] = 0;
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106 if (s > size) s = size;
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107 n = isoread(buffer, s);
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108 movehi();
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109 if (n != -1) {
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110 p->base += n;
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111 size -= n;
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112 }
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113 if (s != n) break;
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114 }
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115 initrd_size = p->base - initrd_addr;
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116 p->base += p->align - 1;
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117 p->base &= - p->align;
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118 }
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119
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pascal@13691
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120 static unsigned setupofs = 0;
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121
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pascal@13691
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122 void movesetup(void)
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123 {
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pascal@13691
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124 #asm
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pascal@13691
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125 pusha
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pascal@13691
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126 push #SETUP_SEGMENT
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127 pop es
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128 mov si, #_buffer
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129 mov di, _setupofs
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130 mov cx, #BUFFERSZ/2
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131 rep
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132 movsw
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133 mov _setupofs, di
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134 popa
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pascal@13691
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135 #endasm
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pascal@13691
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136 }
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pascal@13691
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137
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pascal@13691
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138 void loadkernel(void)
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139 {
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pascal@13691
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140 unsigned setup, n = BUFFERSZ;
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141 unsigned long syssize = 0;
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142
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143 do {
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144 isoread(buffer, n);
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pascal@13691
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145 if (setupofs == 0) {
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pascal@13691
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146 if (* (unsigned short *) (buffer + BOOTFLAG) != 0xAA55)
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147 die("The kernel is not bootable");
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148 setup = (1 + buffer[SETUPSECTORS]) << 9;
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pascal@13691
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149 if (setup == 512) setup = 5 << 9;
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150 syssize = * (unsigned long *) (buffer + SYSSIZE) << 4;
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pascal@13691
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151 version = * (unsigned short *) (buffer + VERSION);
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pascal@13691
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152 #define HDRS 0x53726448
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pascal@13691
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153 if (* (unsigned long *) (buffer + HEADER) != HDRS)
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pascal@13691
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154 version = 0;
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pascal@13691
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155 if (!version || !(buffer[LOADFLAGS] & 1)) {
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pascal@13691
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156 #undef ZIMAGE_SUPPORT /* Does not work... */
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pascal@13691
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157 #ifdef ZIMAGE_SUPPORT
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pascal@13691
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158 #asm
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pascal@13691
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159 pusha
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pascal@13691
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160 mov cx, #0x8000
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161 mov es, cx
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pascal@13691
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162 xor si, si
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163 xor di, di
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164 rep
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pascal@13691
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165 movsw
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pascal@13691
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166 push es
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pascal@13691
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167 pop ds
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pascal@13691
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168 push es
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pascal@13691
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169 pop ss
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170 popa
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pascal@13691
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171 jmpi relocated, #0x8000
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pascal@13691
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172 relocated:
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pascal@13691
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173 #endasm
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pascal@13691
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174 kernelmem.base = 0x10000;
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pascal@13691
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175 if (syssize > 0x70000)
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pascal@13691
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176 #endif
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pascal@13691
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177 die("Not a bzImage format");
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pascal@13691
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178 }
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pascal@13691
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179 if (version < 0x204)
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180 syssize &= 0x000FFFFFUL;
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pascal@13691
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181 if (version) {
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pascal@13691
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182 #ifdef REALMODE_SWITCH
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183 * (unsigned short *) (buffer + RMSWOFS) =
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pascal@13691
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184 realmode_switch;
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185 * (unsigned short *) (buffer + RMSWSEG) =
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186 getcs();
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187 #endif
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pascal@13691
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188 * (unsigned short *) (buffer + HEAPPTR) =
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pascal@13691
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189 0x9B00;
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pascal@13691
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190 // buffer[LOADFLAGS] |= 0x80;
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pascal@13691
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191 * (unsigned short *) (buffer + LOADERTYPE) |=
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192 0x80FF;
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pascal@13691
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193 }
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pascal@13691
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194 }
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pascal@13691
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195 movesetup();
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196 setup -= n;
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197 n = (setup > BUFFERSZ) ? BUFFERSZ : setup;
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pascal@13691
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198 } while (setup > 0);
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199
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pascal@13691
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200 load(&kernelmem, syssize);
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pascal@13691
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201 }
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pascal@13691
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202
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pascal@13691
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203 void loadinitrd(void)
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pascal@13691
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204 {
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pascal@13691
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205 if (version)
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pascal@13691
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206 load(&initrdmem, isofilesize);
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pascal@13691
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207 }
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pascal@13691
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208
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pascal@13691
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209 void bootlinux(char *cmdline)
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pascal@13691
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210 {
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pascal@13691
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211 #asm
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pascal@13691
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212 push #SETUP_SEGMENT
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pascal@13691
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213 pop es
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pascal@13691
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214 mov eax, _initrd_addr
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215 or eax, eax
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216 jz no_initrd
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217 mov di, #0x218
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218 stosd
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pascal@13691
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219 mov eax, _initrd_size
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220 stosd
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pascal@13691
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221 no_initrd:
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pascal@13691
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222 #endasm
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pascal@13691
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223 if (cmdline) {
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pascal@13691
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224 if (version <= 0x201) {
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pascal@13691
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225 #asm
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pascal@13691
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226 mov di, #0x0020
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pascal@13691
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227 mov ax, #0xA33F
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pascal@13691
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228 stosw
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pascal@13691
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229 mov ax, #CMDLINE_OFFSET
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pascal@13691
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230 stosw
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pascal@13691
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231 #endasm
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pascal@13691
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232 }
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pascal@13691
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233 else {
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pascal@13691
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234 #asm
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pascal@13691
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235 mov di, #0x0228
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pascal@13691
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236 mov eax, #SETUP_SEGMENT*16+CMDLINE_OFFSET
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pascal@13691
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237 stosd
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pascal@13691
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238 #endasm
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pascal@13691
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239 }
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pascal@13691
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240 #asm
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pascal@13691
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241 xchg ax, di
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pascal@13691
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242 mov si, .bootlinux.cmdline[bp]
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pascal@13691
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243 copy:
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pascal@13691
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244 lodsb
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pascal@13691
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245 stosb
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pascal@13691
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246 or al,al
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pascal@13691
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247 jne copy
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pascal@13691
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248 #endasm
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pascal@13691
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249 }
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pascal@13691
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250 #asm
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pascal@13691
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251 push es
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pascal@13691
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252 pop ds
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pascal@13691
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253 push ds
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pascal@13691
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254 pop ss
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pascal@13691
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255 mov sp, #CMDLINE_OFFSET
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pascal@13691
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256 jmpi 0, #0x9020
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pascal@13691
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257 #endasm
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pascal@13691
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258 }
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