rev |
line source |
pascal@19538
|
1 ;***************************************************************
|
pascal@19538
|
2 ;****** This file is distributed under GPL
|
pascal@19538
|
3 ;***************************************************************
|
pascal@19538
|
4 ;VDPI init:
|
pascal@19538
|
5 ;Call char* prepare_vcpi(void *pagebuf) first to
|
pascal@19538
|
6 ;initialize paging tables needed for vm86.
|
pascal@19538
|
7 ;pagebuf needs to be 8k+4 bytes. Returns ptr to 1st unused byte.
|
pascal@19538
|
8 ;Then call int get_vcpi_interface(). Returns 1 if ok, 0 if bad.
|
pascal@19538
|
9 ;
|
pascal@19538
|
10 ;VCPI use:
|
pascal@19538
|
11 ;u32* malloc_vcpi(u32 size) - source in HIMEM.CPP
|
pascal@19538
|
12 ; Returns ptr to mallocated zero-terminated list of 4k page addrs
|
pascal@19538
|
13 ; Addresses are sorted in ascending order
|
pascal@19538
|
14 ; Never fails (will die if not enough mem)
|
pascal@19538
|
15 ;void read2vcpi(int fd, u32* vp, u32 size,
|
pascal@19538
|
16 ;void* xfer_buf, u16 xfer_size) - source in HIMEM.CPP
|
pascal@19538
|
17 ; Reads opened fd data into malloc_vcpi'ed memory
|
pascal@19538
|
18 ; Dies if file isn't exactly 'size' bytes long
|
pascal@19538
|
19 ; Needs intermediate buffer of exactly Nx4k bytes
|
pascal@19538
|
20 ;void memcpy_vcpi(u32 dstofs,u16 srcseg,u32 srcofs)
|
pascal@19538
|
21 ; copies 4k from conventional memory to VCPI
|
pascal@19538
|
22 ;void _vm2rm()
|
pascal@19538
|
23 ; switches you from vm86 to plain real mode
|
pascal@19538
|
24
|
pascal@19538
|
25
|
pascal@19538
|
26 ideal
|
pascal@21984
|
27 %PAGESIZE 1000
|
pascal@19538
|
28 %crefref
|
pascal@19538
|
29 %noincl
|
pascal@19538
|
30 %nomacs
|
pascal@19538
|
31 p386
|
pascal@19538
|
32
|
pascal@19538
|
33 ;****** Stuff for declaring descriptors
|
pascal@19538
|
34 struc descr
|
pascal@19538
|
35 limit dw ?
|
pascal@19538
|
36 base0 dw ?
|
pascal@19538
|
37 base16 db ?
|
pascal@19538
|
38 type db ?
|
pascal@19538
|
39 limit16 db ?
|
pascal@19538
|
40 base24 db ?
|
pascal@19538
|
41 ends descr
|
pascal@19538
|
42 macro descriptor name,typ,plevel,present,limit,gran,base
|
pascal@19538
|
43 ;;name descr <limit and 0ffffh,base and 0ffffh,low (base shr 16),typ or plevel or present,(limit shr 16) or gran,high (base shr 16)>
|
pascal@19538
|
44 name descr <limit and 0ffffh,base ,0 ,typ or plevel or present,(limit shr 16) or gran,0 >
|
pascal@19538
|
45 endm
|
pascal@19538
|
46 ; decriptor types (bit0..4 of descr.type )
|
pascal@19538
|
47 tss386_avail = 09h
|
pascal@19538
|
48 data_seg = 00010000b ; data segment
|
pascal@19538
|
49 expand_down = 00000100b ; =1 limit counts down from base
|
pascal@19538
|
50 writable = 00000010b ; =1 if write access allowed to data segment
|
pascal@19538
|
51 code_seg = 00011000b ; code segment
|
pascal@19538
|
52 conforming = 00000100b ; =1 code can be accesses and executed at any PL
|
pascal@19538
|
53 readable = 00000010b ; =1 if code also can be read (cannot be ovwritten)
|
pascal@19538
|
54 ; privilege levels (bit5..6 of descr.type )
|
pascal@19538
|
55 priv0 = 00000000b
|
pascal@19538
|
56 priv1 = 00100000b
|
pascal@19538
|
57 priv2 = 01000000b
|
pascal@19538
|
58 priv3 = 01100000b
|
pascal@19538
|
59 ; segment present bit (bit7 of descr.type )
|
pascal@19538
|
60 is_present = 10000000b
|
pascal@19538
|
61 not_present = 00000000b
|
pascal@19538
|
62 ;definition of granularity ( bits6..7 in descr.limit16 )
|
pascal@19538
|
63 gran_byte = 00000000b
|
pascal@19538
|
64 gran_page = 10000000b ; 4k granularity
|
pascal@19538
|
65 use_16 = 00000000b
|
pascal@19538
|
66 use_32 = 01000000b
|
pascal@19538
|
67
|
pascal@19538
|
68 ;****** rm32,imm16 helpers
|
pascal@19538
|
69 macro addzx_e rm,i
|
pascal@19538
|
70 db 66h
|
pascal@19538
|
71 add rm,i
|
pascal@19538
|
72 dw 0
|
pascal@19538
|
73 endm
|
pascal@19538
|
74
|
pascal@19538
|
75
|
pascal@20534
|
76 group DGROUP _TEXT,_BSS
|
pascal@19538
|
77 assume cs:DGROUP,ds:DGROUP
|
pascal@19538
|
78
|
pascal@20534
|
79 segment _BSS byte public use16 'BSS'
|
pascal@20534
|
80
|
pascal@20534
|
81 tss dd ?,? ;enough, we'll never use it anyway
|
pascal@20534
|
82
|
pascal@20534
|
83 ends _BSS
|
pascal@20534
|
84
|
pascal@20534
|
85 segment _TEXT byte public use16 'CODE'
|
pascal@19538
|
86
|
pascal@19538
|
87 label gdt byte
|
pascal@19538
|
88 gdt_null descr <?> ;0000
|
pascal@19538
|
89 gdt_vcpi descr <?> ;0008
|
pascal@19538
|
90 gdt_vcpi2 descr <?> ;0010
|
pascal@19538
|
91 gdt_vcpi3 descr <?> ;0018
|
pascal@19538
|
92 descriptor gdt_abs ,(data_seg+writable),priv0,is_present,0fffffh,(gran_page+use_32),0
|
pascal@19538
|
93 ;Note: code/data segs must be flagged use16 (i.e. use ip/sp, not eip/esp)
|
pascal@19538
|
94 ;Note: base addrs will be fixed up in prepare_vcpi()
|
pascal@19538
|
95 descriptor gdt_code,(code_seg+readable),priv0,is_present,0fffffh,(gran_page+use_16),0
|
pascal@20751
|
96 global gdt_data:descr
|
pascal@19538
|
97 descriptor gdt_data,(data_seg+writable),priv0,is_present,0fffffh,(gran_page+use_16),0
|
pascal@19538
|
98 descriptor gdt_tss ,tss386_avail ,priv0,is_present,0ffh ,gran_byte ,<offset tss>
|
pascal@19538
|
99 SEL_VCPI = (gdt_vcpi - gdt_null)
|
pascal@19538
|
100 SEL_TSS = (gdt_tss - gdt_null)
|
pascal@19538
|
101 SEL_ABS = (gdt_abs - gdt_null)
|
pascal@19538
|
102 SEL_CODE = (gdt_code - gdt_null)
|
pascal@19538
|
103 SEL_DATA = (gdt_data - gdt_null)
|
pascal@19538
|
104
|
pascal@19538
|
105 label gdtr pword
|
pascal@19538
|
106 gdt_lim dw 0ffffh
|
pascal@19538
|
107 gdt_base dw offset gdt,0
|
pascal@19538
|
108
|
pascal@19538
|
109 ;Note: layout dictated by vcpi api, don't rearrange!
|
pascal@19538
|
110 label sw2pm_params byte
|
pascal@19538
|
111 ;Note: base addrs will be fixed up in prepare_vcpi()
|
pascal@19634
|
112 label pagedir_laddr dword
|
pascal@19906
|
113 sw2pm_cr3 dd 1000h
|
pascal@19538
|
114 sw2pm_gdtr_ptr dw offset gdtr,0
|
pascal@19538
|
115 sw2pm_idtr_ptr dw offset idtr,0
|
pascal@19538
|
116 sw2pm_ldtr dw 0 ;we don't need it
|
pascal@19538
|
117 sw2pm_tr dw SEL_TSS ;vcpi thinks we need it... can't set to 0
|
pascal@19634
|
118 sw2pm_jumpaddr dd 0
|
pascal@19538
|
119 dw SEL_CODE
|
pascal@19538
|
120
|
pascal@19634
|
121 vcpi_pm_entry dd 0
|
pascal@19634
|
122 dw SEL_VCPI
|
pascal@19634
|
123
|
pascal@19634
|
124 label idtr pword
|
pascal@19634
|
125 idt_lim dw 03ffh ;we won't enable ints,
|
pascal@19634
|
126 idt_base dd 0 ; so let's leave it the same as for rm
|
pascal@19634
|
127
|
pascal@19538
|
128
|
pascal@19538
|
129 ;***************************************************************
|
pascal@19538
|
130 ;char* prepare_vcpi(void *pagebuf);
|
pascal@19538
|
131 ;****** Return: AX=>first unused byte in pagebuf
|
pascal@19538
|
132 ;****** Uses: Flags
|
pascal@19538
|
133 ;***************************************************************
|
pascal@19538
|
134 global prepare_vcpi:near
|
pascal@20486
|
135 proc prepare_vcpi near
|
pascal@19538
|
136
|
pascal@19538
|
137 ;pop ax
|
pascal@19538
|
138 ;pop bx ;pgbuf
|
pascal@19538
|
139 ;push bx
|
pascal@19538
|
140 ;push ax
|
pascal@19538
|
141
|
pascal@19538
|
142 ;Calculate pagedir/page0 addrs, initialize cr3 and pagedir[0]
|
pascal@19538
|
143 xor eax,eax
|
pascal@19538
|
144 ; heap_top = prepare_vcpi(malloc_or_die(8*1024+4));
|
pascal@21777
|
145 mov ah,8*1024/256
|
pascal@19538
|
146 extrn malloc_or_die:near
|
pascal@21777
|
147 call malloc_or_die
|
pascal@19538
|
148
|
pascal@19538
|
149 mov edx,cs
|
pascal@21777
|
150 shl edx,4 ;edx = linear addr of CS
|
pascal@19634
|
151 mov si,offset gdt_vcpi
|
pascal@19538
|
152 ; Fix up base of some gdt descriptors
|
pascal@19538
|
153 ; Note: 'add [dword xx.base0],edx' actually updates 24 bit quantity!
|
pascal@19538
|
154 ; Do NOT replace with mov!
|
pascal@19919
|
155 mov ebx,10000h-28h
|
pascal@19906
|
156 add [dword bx+si+sw2pm_idtr_ptr-gdt_vcpi+28h],edx
|
pascal@19634
|
157 @@fixup:
|
pascal@19906
|
158 add [dword bx+si+(gdt_code.base0)-gdt_vcpi+28h],edx
|
pascal@19919
|
159 add bx,8
|
pascal@19906
|
160 js @@fixup
|
pascal@19919
|
161 mov bh,10h
|
pascal@19538
|
162 add eax,edx
|
pascal@19919
|
163 and ax,0f000h ;eax = 4k aligned linear addr of pagebuf
|
pascal@19919
|
164 add eax,ebx ;eax=page0 linear addr
|
pascal@19906
|
165 add [si+sw2pm_cr3-gdt_vcpi],eax
|
pascal@19919
|
166 mov edi,eax
|
pascal@19919
|
167 sub edi,edx
|
pascal@19538
|
168 mov al,3 ;add present+writable bits
|
pascal@19919
|
169 mov [bx+di],eax ;stuff it into pagedir[0]
|
pascal@19634
|
170 push ds
|
pascal@19919
|
171 pop es ;es:di->page0,es:di+1000h->pagedir
|
pascal@19538
|
172 ;page directory will use only one entry (4 bytes):
|
pascal@19538
|
173 ;cr3 => pagedir => page0 => ########
|
pascal@19538
|
174 ; (1 entry) (1024 => # 4M #
|
pascal@19538
|
175 ; entries)=> # page #
|
pascal@19538
|
176 ; => ########
|
pascal@19538
|
177 ; Return
|
pascal@19919
|
178 lea ax,[bx+di+4]
|
pascal@19538
|
179 extrn _heap_top:word
|
pascal@19538
|
180 mov [_heap_top],ax
|
pascal@19538
|
181 ;ret
|
pascal@19538
|
182
|
pascal@20486
|
183 endp prepare_vcpi
|
pascal@19538
|
184
|
pascal@19538
|
185
|
pascal@19538
|
186 ;***************************************************************
|
pascal@19538
|
187 ;int get_vcpi_interface();
|
pascal@19634
|
188 ;****** Return: Z - page mapping for low 640k is 1:1
|
pascal@19634
|
189 ;****** NZ - otherwise (it's bad)
|
pascal@19538
|
190 ;****** Uses: Flags
|
pascal@19538
|
191 ;***************************************************************
|
pascal@20486
|
192 ;global _get_vcpi_interface:near
|
pascal@19538
|
193 proc _get_vcpi_interface near
|
pascal@19538
|
194
|
pascal@19538
|
195 ;push si di
|
pascal@19538
|
196
|
pascal@19538
|
197 ; Get and save VCPI pm interface
|
pascal@19634
|
198 ;mov si,offset gdt_vcpi ;DS:DI => 3 GDT entries for VCPI
|
pascal@19546
|
199 ;mov di,[si+page0_ofs-gdt_vcpi] ;ES:DI => page0
|
pascal@19546
|
200 ;push ds
|
pascal@19546
|
201 ;pop es
|
pascal@19634
|
202 push di
|
pascal@19538
|
203 mov ax,0DE01h ;get vcpi pm interface
|
pascal@19538
|
204 int 67h
|
pascal@19634
|
205 xchg [vcpi_pm_entry],ebx ;clear ebx
|
pascal@19634
|
206 ;xor bx,bx
|
pascal@19538
|
207
|
pascal@19538
|
208 ; Check that mapping for low 640k is 1:1
|
pascal@19634
|
209 pop si ; [page0_ofs]
|
pascal@19571
|
210 ;cld
|
pascal@19538
|
211 @@map_chk:
|
pascal@19538
|
212 lodsd
|
pascal@19538
|
213 shr eax,12
|
pascal@19538
|
214 cmp ax,bx
|
pascal@19538
|
215 jne @@bad
|
pascal@19538
|
216 inc bx
|
pascal@19634
|
217 cmp al,((640*1024) shr 12)-1
|
pascal@19538
|
218 jne @@map_chk
|
pascal@19538
|
219 ; Return
|
pascal@19538
|
220 @@bad:
|
pascal@19538
|
221 ret
|
pascal@19538
|
222 endp _get_vcpi_interface
|
pascal@19538
|
223
|
pascal@19538
|
224
|
pascal@19538
|
225 ;***************************************************************
|
pascal@19538
|
226 ;void memcpy_vcpi(u32 dstofs,u16 srcseg,u32 srcofs);
|
pascal@19538
|
227 ;***************************************************************
|
pascal@19538
|
228 ;****** Copies PAGE_SIZE bytes
|
pascal@19538
|
229 ;****** Uses: Flags
|
pascal@19538
|
230 ;***************************************************************
|
pascal@20534
|
231 global vcpi_pm_copy_routine:near
|
pascal@20534
|
232 proc vcpi_pm_copy_routine near
|
pascal@19538
|
233
|
pascal@19538
|
234 arg dstofs :dword, \
|
pascal@19538
|
235 srcseg :word, \
|
pascal@19538
|
236 srcofs :dword = PARAM_SIZE
|
pascal@19538
|
237
|
pascal@19538
|
238 struc pm_regs
|
pascal@19538
|
239 $$retaddr dw ?
|
pascal@19538
|
240 $$edi dd ?
|
pascal@19538
|
241 $$esi dd ?
|
pascal@19538
|
242 $$ebp dd ?
|
pascal@19538
|
243 $$esp dd ?
|
pascal@19538
|
244 $$ebx dd ?
|
pascal@19538
|
245 $$edx dd ?
|
pascal@19538
|
246 $$ecx dd ?
|
pascal@19538
|
247 $$eax dd ?
|
pascal@19538
|
248 ends
|
pascal@19538
|
249
|
pascal@19538
|
250 ;***************************************************************
|
pascal@19538
|
251 ;****** Helper: goes into 16bit pm and calls routine (addr on stk)
|
pascal@19538
|
252 ;***************************************************************
|
pascal@19538
|
253 mov bp,sp ; ss:bp => struct pm_regs
|
pascal@19538
|
254
|
pascal@19538
|
255 xor ax,ax ; IRET stack for return to vm
|
pascal@19538
|
256 push ax gs ; (9 dwords)
|
pascal@19538
|
257 push ax fs ;
|
pascal@19538
|
258 push ax ds ;
|
pascal@19538
|
259 push ax es ;
|
pascal@19538
|
260 push ax ss ;
|
pascal@19538
|
261 push ebp ; esp
|
pascal@19538
|
262 pushfd ; eflags: IF saved here
|
pascal@19538
|
263 push ax cs ;
|
pascal@19538
|
264 push ax ;\eip
|
pascal@19538
|
265 push offset @@vm_ret ;/
|
pascal@19538
|
266
|
pascal@19538
|
267 ;;mov [saved_xx],xx ;use if your vcpi trashes bp/etc
|
pascal@19538
|
268
|
pascal@19634
|
269 call switch_to_pm
|
pascal@19634
|
270
|
pascal@19538
|
271 ; Now we are in 16-bit protected mode
|
pascal@19538
|
272 mov ax,SEL_DATA
|
pascal@19538
|
273 mov ss,ax
|
pascal@19538
|
274 ;;mov ds,ax
|
pascal@19538
|
275 ;;mov es,ax
|
pascal@19538
|
276 ;;mov fs,ax
|
pascal@19538
|
277 ;;mov gs,ax
|
pascal@19538
|
278 assume nothing
|
pascal@19538
|
279 assume cs:DGROUP
|
pascal@19538
|
280
|
pascal@19538
|
281 ;;mov xx,[saved_xx] ;use if your vcpi trashes bp/etc
|
pascal@19538
|
282 lea sp,[bp-9*4] ;else we can do this trick with bp
|
pascal@19538
|
283
|
pascal@19538
|
284 ; Call the routine (bp points to params on stack if any)
|
pascal@19538
|
285 mov bp,[word (pm_regs bp).$$ebp] ;ss:bp => params
|
pascal@20534
|
286 call do_memcpy_vcpi
|
pascal@19538
|
287
|
pascal@19538
|
288 ; Ok, let's return to vm
|
pascal@19634
|
289 mov ax,0DE0Ch ; maybe we need whole eax?
|
pascal@19538
|
290 cli ; to be safe
|
pascal@19538
|
291 clts ;
|
pascal@20534
|
292 ;;push SEL_ABS ; vcpi wants ds=all_addrspace
|
pascal@20534
|
293 ;;pop ds ;
|
pascal@19538
|
294 call [pword cs:vcpi_pm_entry]
|
pascal@19538
|
295 @@vm_ret:
|
pascal@19538
|
296 ; Now we are in vm86 mode. Sregs, esp, eflags (IF) restored from IRET stack
|
pascal@19538
|
297 ret
|
pascal@19538
|
298
|
pascal@19538
|
299 ;***************************************************************
|
pascal@19634
|
300 switch_to_pm:
|
pascal@19634
|
301 assume cs:DGROUP,ds:DGROUP
|
pascal@19634
|
302 pop [word sw2pm_jumpaddr]
|
pascal@19634
|
303 ;mov [word sw2pm_jumpaddr+2],0
|
pascal@19634
|
304 ;mov [word sw2pm_jumpaddr+4],SEL_CODE
|
pascal@19634
|
305 mov esi,cs
|
pascal@19634
|
306 shl esi,4
|
pascal@19634
|
307 addzx_e si,<offset sw2pm_params>
|
pascal@19634
|
308 mov ax,0DE0Ch ; vcpi: switch to pm
|
pascal@19634
|
309 cli
|
pascal@19634
|
310 int 67h
|
pascal@19634
|
311
|
pascal@19634
|
312 ;***************************************************************
|
pascal@19538
|
313 ;****** Helper: This is where real copy is done
|
pascal@19538
|
314 ;***************************************************************
|
pascal@19538
|
315 global do_memcpy_vcpi:near
|
pascal@19538
|
316 label do_memcpy_vcpi near
|
pascal@19538
|
317
|
pascal@19538
|
318 ; Note: ss:bp => params
|
pascal@19538
|
319 ; Move data
|
pascal@20534
|
320 mov al,SEL_ABS
|
pascal@19634
|
321 mov ds,ax
|
pascal@19634
|
322 mov es,ax
|
pascal@19538
|
323 assume nothing
|
pascal@19538
|
324 assume cs:DGROUP
|
pascal@19538
|
325
|
pascal@19538
|
326 ; Set up target addr:
|
pascal@19538
|
327 ; replace page mapping for page at 0 so
|
pascal@19538
|
328 ; that it points to dstofs
|
pascal@19538
|
329 mov eax,[dstofs]
|
pascal@19538
|
330 mov al,03h ; writeable, present
|
pascal@19634
|
331 call @@set_mapping
|
pascal@19538
|
332 ;push eax ;X we'll need to restore mapping...
|
pascal@19538
|
333 xor edi,edi ;es:edi => remapped page
|
pascal@19538
|
334
|
pascal@19538
|
335 ; Set up source addr
|
pascal@19538
|
336 mov esi,[srcofs]
|
pascal@19538
|
337
|
pascal@19538
|
338 ; Do copying
|
pascal@19634
|
339 xor ecx,ecx
|
pascal@19634
|
340 mov ch,4096/256
|
pascal@19571
|
341 ;cld
|
pascal@19538
|
342 ;; cmp esi,edi
|
pascal@19538
|
343 ;; jae @@do_copy
|
pascal@19538
|
344 ;; add esi,ecx ;src<dst: we must do
|
pascal@19538
|
345 ;; dec esi ; copy backwards to avoid
|
pascal@19538
|
346 ;; add edi,ecx ; overwrite bug
|
pascal@19538
|
347 ;; dec edi ;
|
pascal@19538
|
348 ;; std ;
|
pascal@19538
|
349 ;;@@do_copy:
|
pascal@19538
|
350 db 67h ;address width override for esi/edi
|
pascal@19634
|
351 rep movsb
|
pascal@19538
|
352 ;; cld
|
pascal@19538
|
353
|
pascal@19538
|
354 ; Restore page mapping for page at 0
|
pascal@19538
|
355 ;pop eax ;X
|
pascal@19634
|
356 @@set_mapping:
|
pascal@19906
|
357 mov esi,[cs:sw2pm_cr3]
|
pascal@19906
|
358 xchg [esi-1000h],eax ; restore page0[0]
|
pascal@19538
|
359 mov ecx,cr3 ; reload TLB cache
|
pascal@19538
|
360 mov cr3,ecx ;
|
pascal@19538
|
361 ; Return
|
pascal@19907
|
362 vcpi_ret:
|
pascal@19538
|
363 ret
|
pascal@19538
|
364
|
pascal@20534
|
365 endp vcpi_pm_copy_routine
|
pascal@20534
|
366 assume cs:DGROUP,ds:DGROUP
|
pascal@19538
|
367
|
pascal@19538
|
368
|
pascal@19538
|
369 ;***************************************************************
|
pascal@19538
|
370 ;void _vm2rm();
|
pascal@19538
|
371 ;***************************************************************
|
pascal@19538
|
372 ;****** Uses: Flags
|
pascal@19538
|
373 ;***************************************************************
|
pascal@19538
|
374 global _vm2rm:near
|
pascal@19538
|
375 proc _vm2rm near
|
pascal@19538
|
376
|
pascal@20473
|
377 ifdef NO386
|
pascal@19825
|
378 p8086
|
pascal@19580
|
379 extrn _vcpi:byte
|
pascal@19580
|
380 test [_vcpi],-1
|
pascal@20473
|
381 else
|
pascal@20473
|
382 p386
|
pascal@20473
|
383 smsw ax ;SMSW cannot be trapped! :-)
|
pascal@20473
|
384 and al,1 ;MSW_PE
|
pascal@20473
|
385 endif
|
pascal@19907
|
386 jz vcpi_ret
|
pascal@19825
|
387 p386
|
pascal@19907
|
388 pop ax
|
pascal@19907
|
389 push cs ;*
|
pascal@19907
|
390 push ax
|
pascal@19634
|
391 push si
|
pascal@19538
|
392 push ds
|
pascal@20453
|
393 extrn sssp:word
|
pascal@20453
|
394 mov [sssp],sp
|
pascal@20473
|
395 ;mov [sssp+2],ss
|
pascal@19538
|
396
|
pascal@19634
|
397 call switch_to_pm
|
pascal@19634
|
398
|
pascal@19538
|
399 ; Now we are in 16-bit protected mode
|
pascal@19538
|
400 mov ax,SEL_DATA ; load data sregs with limit >=64k
|
pascal@19538
|
401 mov ss,ax ; or you may get limit violations
|
pascal@19538
|
402 mov ds,ax ; later in rm
|
pascal@19634
|
403 ;mov es,ax ; (actually I prefer 4gig limits :-)
|
pascal@19571
|
404 ;mov fs,ax ;
|
pascal@19571
|
405 ;mov gs,ax ;
|
pascal@19538
|
406
|
pascal@19538
|
407 ; Black magic here
|
pascal@19538
|
408 mov eax,cr0
|
pascal@19538
|
409 and eax,7ffffffeh ; clear PG,P bits
|
pascal@19538
|
410 mov cr0,eax ; look mommy, we're in rm now!
|
pascal@19538
|
411 mov cr3,eax ; flush TLB cache
|
pascal@19538
|
412
|
pascal@19538
|
413 ; Now we are in rm, but not yet: have to restore sregs:
|
pascal@20453
|
414 lss sp,[dword sssp]; SS
|
pascal@19538
|
415 pop ds ; DS
|
pascal@19907
|
416 pop si
|
pascal@19538
|
417 retf ; CS
|
pascal@19571
|
418
|
pascal@19538
|
419 endp _vm2rm
|
pascal@19538
|
420
|
pascal@19538
|
421 ends _TEXT
|
pascal@19538
|
422
|
pascal@19538
|
423 end
|
pascal@19538
|
424
|
pascal@19538
|
425 ;###### END OF FILE ############################################
|