1 // 16bit system callbacks
3 // Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net>
4 // Copyright (C) 2002 MandrakeSoft S.A.
6 // This file may be distributed under the terms of the GNU GPLv3 license.
8 #include "util.h" // irq_restore
9 #include "biosvar.h" // BIOS_CONFIG_TABLE
10 #include "ioport.h" // inb
11 #include "memmap.h" // E820_RAM
12 #include "pic.h" // eoi_pic2
14 // Use PS2 System Control port A to set A20 enable
18 // get current setting first
19 u8 newval, oldval = inb(PORT_A20);
21 newval = oldval | 0x02;
23 newval = oldval & ~0x02;
24 outb(newval, PORT_A20);
26 return (newval & 0x02) != 0;
30 handle_152400(struct bregs *regs)
33 set_code_success(regs);
37 handle_152401(struct bregs *regs)
40 set_code_success(regs);
44 handle_152402(struct bregs *regs)
46 regs->al = !!(inb(PORT_A20) & 0x20);
47 set_code_success(regs);
51 handle_152403(struct bregs *regs)
54 set_code_success(regs);
58 handle_1524XX(struct bregs *regs)
60 set_code_fail(regs, RET_EUNSUPPORTED);
64 handle_1524(struct bregs *regs)
67 case 0x00: handle_152400(regs); break;
68 case 0x01: handle_152401(regs); break;
69 case 0x02: handle_152402(regs); break;
70 case 0x03: handle_152403(regs); break;
71 default: handle_1524XX(regs); break;
75 // removable media eject
77 handle_1552(struct bregs *regs)
79 set_code_success(regs);
83 handle_1587(struct bregs *regs)
85 // +++ should probably have descriptor checks
86 // +++ should have exception handlers
88 u8 prev_a20_enable = set_a20(1); // enable A20 line
90 // 128K max of transfer on 386+ ???
91 // source == destination ???
93 // ES:SI points to descriptor table
94 // offset use initially comments
95 // ==============================================
96 // 00..07 Unused zeros Null descriptor
97 // 08..0f GDT zeros filled in by BIOS
98 // 10..17 source ssssssss source of data
99 // 18..1f dest dddddddd destination of data
100 // 20..27 CS zeros filled in by BIOS
101 // 28..2f SS zeros filled in by BIOS
108 // check for access rights of source & dest here
110 // Initialize GDT descriptor
111 SET_SEG(ES, regs->es);
113 u16 base15_00 = (regs->es << 4) + si;
114 u16 base23_16 = regs->es >> 12;
115 if (base15_00 < (u16)(regs->es<<4))
117 SET_VAR(ES, *(u16*)(si+0x08+0), 47); // limit 15:00 = 6 * 8bytes/descriptor
118 SET_VAR(ES, *(u16*)(si+0x08+2), base15_00);// base 15:00
119 SET_VAR(ES, *(u8 *)(si+0x08+4), base23_16);// base 23:16
120 SET_VAR(ES, *(u8 *)(si+0x08+5), 0x93); // access
121 SET_VAR(ES, *(u16*)(si+0x08+6), 0x0000); // base 31:24/reserved/limit 19:16
123 // Initialize CS descriptor
124 SET_VAR(ES, *(u16*)(si+0x20+0), 0xffff);// limit 15:00 = normal 64K limit
125 SET_VAR(ES, *(u16*)(si+0x20+2), 0x0000);// base 15:00
126 SET_VAR(ES, *(u8 *)(si+0x20+4), 0x000f);// base 23:16
127 SET_VAR(ES, *(u8 *)(si+0x20+5), 0x9b); // access
128 SET_VAR(ES, *(u16*)(si+0x20+6), 0x0000);// base 31:24/reserved/limit 19:16
130 // Initialize SS descriptor
131 u16 ss = GET_SEG(SS);
133 base23_16 = ss >> 12;
134 SET_VAR(ES, *(u16*)(si+0x28+0), 0xffff); // limit 15:00 = normal 64K limit
135 SET_VAR(ES, *(u16*)(si+0x28+2), base15_00);// base 15:00
136 SET_VAR(ES, *(u8 *)(si+0x28+4), base23_16);// base 23:16
137 SET_VAR(ES, *(u8 *)(si+0x28+5), 0x93); // access
138 SET_VAR(ES, *(u16*)(si+0x28+6), 0x0000); // base 31:24/reserved/limit 19:16
140 u16 count = regs->cx;
142 // Load new descriptor tables
143 "lgdtw %%es:0x8(%%si)\n"
144 "lidtw %%cs:pmode_IDT_info\n"
147 "movl %%cr0, %%eax\n"
149 "movl %%eax, %%cr0\n"
151 // far jump to flush CPU queue after transition to protected mode
152 "ljmpw $0x0020, $1f\n"
155 // GDT points to valid descriptor table, now load DS, ES
156 "movw $0x10, %%ax\n" // 010 000 = 2nd descriptor in table, TI=GDT, RPL=00
158 "movw $0x18, %%ax\n" // 011 000 = 3rd descriptor in table, TI=GDT, RPL=00
161 // move CX words from DS:SI to ES:DI
166 // reset PG bit in CR0 ???
167 "movl %%cr0, %%eax\n"
169 "movl %%eax, %%cr0\n"
171 // far jump to flush CPU queue after transition to real mode
172 "ljmpw $0xf000, $2f\n"
175 // restore IDT to normal real-mode defaults
176 "lidt %%cs:rmode_IDT_info\n"
178 // Restore %ds (from %ss)
181 : "+c"(count), "+S"(si)
182 : : "eax", "di", "cc"); // XXX - also clobbers %es
184 set_a20(prev_a20_enable);
186 set_code_success(regs);
189 // Get the amount of extended memory (above 1M)
191 handle_1588(struct bregs *regs)
193 u32 rs = GET_EBDA(ram_size);
195 // According to Ralf Brown's interrupt the limit should be 15M,
196 // but real machines mostly return max. 63M.
197 if (rs > 64*1024*1024)
198 regs->ax = 63 * 1024;
200 regs->ax = (rs - 1*1024*1024) / 1024;
204 // Device busy interrupt. Called by Int 16h when no key available
206 handle_1590(struct bregs *regs)
210 // Interrupt complete. Called by Int 16h when key becomes available
212 handle_1591(struct bregs *regs)
216 // keyboard intercept
218 handle_154f(struct bregs *regs)
220 set_fail_silent(regs);
224 handle_15c0(struct bregs *regs)
227 regs->bx = (u32)&BIOS_CONFIG_TABLE;
228 set_code_success(regs);
232 handle_15c1(struct bregs *regs)
234 regs->es = GET_BDA(ebda_seg);
239 handle_15e801(struct bregs *regs)
241 // my real system sets ax and bx to 0
242 // this is confirmed by Ralph Brown list
243 // but syslinux v1.48 is known to behave
244 // strangely if ax is set to 0
245 // regs.u.r16.ax = 0;
246 // regs.u.r16.bx = 0;
248 u32 rs = GET_EBDA(ram_size);
250 // Get the amount of extended memory (above 1M)
251 if (rs > 16*1024*1024) {
254 // Get the amount of extended memory above 16M in 64k blocks
255 regs->dx = (rs - 16*1024*1024) / (64*1024);
257 regs->cx = (rs - 1*1024*1024) / 1024;
261 // Set configured memory equal to extended memory
269 handle_15e820(struct bregs *regs)
271 int count = GET_EBDA(e820_count);
272 if (regs->edx != 0x534D4150 || regs->bx >= count) {
273 set_code_fail(regs, RET_EUNSUPPORTED);
277 struct e820entry *e = &((struct e820entry *)GET_EBDA(e820_loc))[regs->bx];
278 memcpy(MAKE_FARPTR(regs->es, regs->di), e, sizeof(*e));
279 if (regs->bx == count-1)
283 regs->eax = 0x534D4150;
284 regs->ecx = sizeof(*e);
289 handle_15e8XX(struct bregs *regs)
291 set_code_fail(regs, RET_EUNSUPPORTED);
295 handle_15e8(struct bregs *regs)
298 case 0x01: handle_15e801(regs); break;
299 case 0x20: handle_15e820(regs); break;
300 default: handle_15e8XX(regs); break;
305 handle_15XX(struct bregs *regs)
307 set_code_fail(regs, RET_EUNSUPPORTED);
310 // INT 15h System Services Entry Point
312 handle_15(struct bregs *regs)
314 debug_enter(regs, DEBUG_HDL_15);
316 case 0x24: handle_1524(regs); break;
317 case 0x4f: handle_154f(regs); break;
318 case 0x52: handle_1552(regs); break;
319 case 0x53: handle_1553(regs); break;
320 case 0x83: handle_1583(regs); break;
321 case 0x86: handle_1586(regs); break;
322 case 0x87: handle_1587(regs); break;
323 case 0x88: handle_1588(regs); break;
324 case 0x90: handle_1590(regs); break;
325 case 0x91: handle_1591(regs); break;
326 case 0xc0: handle_15c0(regs); break;
327 case 0xc1: handle_15c1(regs); break;
328 case 0xc2: handle_15c2(regs); break;
329 case 0xe8: handle_15e8(regs); break;
330 default: handle_15XX(regs); break;
334 // INT 12h Memory Size Service Entry Point
336 handle_12(struct bregs *regs)
338 debug_enter(regs, DEBUG_HDL_12);
339 regs->ax = GET_BDA(mem_size_kb);
342 // INT 11h Equipment List Service Entry Point
344 handle_11(struct bregs *regs)
346 debug_enter(regs, DEBUG_HDL_11);
347 regs->ax = GET_BDA(equipment_list_flags);
350 // INT 05h Print Screen Service Entry Point
352 handle_05(struct bregs *regs)
354 debug_enter(regs, DEBUG_HDL_05);
357 // INT 10h Video Support Service Entry Point
359 handle_10(struct bregs *regs)
361 debug_enter(regs, DEBUG_HDL_10);
362 // dont do anything, since the VGA BIOS handles int10h requests
368 debug_isr(DEBUG_ISR_nmi);
369 BX_PANIC("NMI Handler called\n");
375 dprintf(3, "math cp init\n");
376 // 80x87 coprocessor installed
377 SETBITS_BDA(equipment_list_flags, 0x02);
378 // Enable IRQ13 (handle_75)
379 unmask_pic2(PIC2_IRQ13);
382 // INT 75 - IRQ13 - MATH COPROCESSOR EXCEPTION
386 debug_isr(DEBUG_ISR_75);
389 outb(0, PORT_MATH_CLEAR);
394 memset(&br, 0, sizeof(br));
395 call16_int(0x02, &br);