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1
2 page
3;-------------------------------------------------------------------
4;
5; This file contains the code to do a pseudo-rom scan looking
6; for possible EMS holes
7;
8;-------------------------------------------------------------------
9
10
11
12romscan proc near
13
14 push ax
15 push dx
16 push cx
17 push di
18
19 push cs ; make es and ds point to segment where messages are
20 pop es
21
22 push cs
23 pop ds
24
25; must do rom scan with interrupts disabled
26
27 cli
28
29;------------------------
30
31 cmp map_count,0 ; no segments specified, do rom scan
32 je no_pages_spec
33
34 mov cx,map_count ; number of segments to check
35 xor di,di ; use di as pointer into table
36
37check_segs:
38 mov ax,map_table.phys_page_segment[di]
39
40 call CHK_FREE_SEGMENT ; check a 16K block
41 jnc segment_ok
42
43; display the error
44
45 mov segment_error,1 ; set segment error flag
46
47
48; display conflict message
49
50 push ax ; save some regs
51 push dx
52 push di
53
54 MOV DI,OFFSET confl_address ; ascii string page frame
55 CALL CNVHEXAT
56
57 MOV DX,OFFSET conflict_msg ; start of message
58 MOV AH,9 ; dos prt string
59 INT 21H ;
60
61 pop di ; restore some regs
62 pop dx
63 pop ax
64
65segment_ok:
66 add di,type mappable_phys_page_struct
67 loop check_segs
68
69;------------------------
70; if there were no conflicts, then exit with no error
71
72 cmp segment_error,0
73 je rom_scan_no_error ; exit with no error (carry = 0)
74
75;------------------------
76
77 MOV DX,OFFSET CRLF ; skip a blank line
78 MOV AH,9 ; dos prt string
79 INT 21H ;
80
81 jmp rom_scan_code
82
83; display no pages message
84
85no_pages_spec:
86 MOV DX,OFFSET NO_PAGES_MSG ; skip a blank line
87 MOV AH,9 ; dos prt string
88 INT 21H
89
90 MOV DX,OFFSET CRLF ; skip a blank line
91 MOV AH,9 ; dos prt string
92 INT 21H ;
93
94;-------------------------------------------------------------------
95;
96; This routine scans the address range from c000 - FFFF looking
97; for 16 K gaps.
98;
99;-------------------------------------------------------------------
100
101rom_scan_code:
102
103 mov ax,0c000h ; start at c000
104 xor bx,bx ; bx holds count of contiguous pages
105 mov cx,15 ; loop counter
106 mov dx,ax ; dx holds start of frame
107
108fam2_loop:
109 call CHK_FREE_SEGMENT ; check a 16K block
110 jc bad_seg
111
112; good 16 segment
113
114 call FoundBlock
115
116 add bx,1 ; add another page to frame counter
117 cmp bx,4 ; 4 means frame is found
118 jne no_frame_yet
119
120; a frame has been found
121
122 mov bx,100 ; make sure we don't look for more frames
123
124no_frame_yet:
125 add ax,0400h ; point to next segment
126 jmp continue_loop
127
128; bad 16 segment
129
130bad_seg:
131 add ax,0400h ; point to next segment
132 cmp bx,100
133 jae continue_loop ; don't reset frame info if one has been found
134
135 xor bx,bx ; clear contiguous page counter
136 mov dx,ax ; make frame pointer point to next page
137
138continue_loop:
139
140 loop fam2_loop
141 jmp rom_scan_exit
142
143
144rom_scan_no_error:
145 clc
146 jmp clean_exit
147
148
149;-------------------------------------------------------------------
150
151rom_scan_exit:
152
153; display frame if found
154
155 cmp bx,100 ; >= 100 means frame was found
156 jb no_frame_exit
157
158 mov ax,dx ; get frame address in ax
159 call FoundFrame ; display frame address
160
161
162no_frame_exit:
163 STC ; carry = 1 means error
164
165clean_exit:
166 sti
167
168
169 pop di
170 pop dx
171 pop cx
172 pop ax
173
174 ret
175
176romscan endp
177
178
179
180;-------------------------------------------------------------------
181;
182; FoundBlock assumes AX = segment address of good 16 K block
183;
184;-------------------------------------------------------------------
185
186FoundBlock proc near
187
188 push ax
189 push dx
190 push es
191 push di
192
193 push cs
194 pop es
195
196 push cs
197 pop ds
198
199 MOV DI,OFFSET hole_address ; ascii string page frame
200 CALL CNVHEXAT
201
202 MOV DX,OFFSET hole_msg ; start of message
203 MOV AH,9 ; dos prt string
204 INT 21H ;
205
206
207 pop di
208 pop es
209 pop dx
210 pop ax
211
212 ret
213
214FoundBlock endp
215
216;-------------------------------------------------------------------
217;
218; FoundFrame assumes AX = segment address of good 64 K block
219;
220;-------------------------------------------------------------------
221
222FoundFrame proc near
223
224 push ax
225 push dx
226 push es
227 push di
228
229 push cs
230 pop es
231
232 push cs
233 pop ds
234
235 MOV DI,OFFSET frame_address ; ascii string page frame
236 CALL CNVHEXAT
237
238 MOV DX,OFFSET frame_msg ; start of message
239 MOV AH,9 ; dos prt string
240 INT 21H ;
241
242
243 pop di
244 pop es
245 pop dx
246 pop ax
247
248 ret
249
250FoundFrame endp
251
252
253
254
255
256
257;-------------------------------------------------------------------
258;-------------------------------------------------------------------
259;-------------------------------------------------------------------
260;-------------------------------------------------------------------
261;-------------------------------------------------------------------
262;-------------------------------------------------------------------
263;-------------------------------------------------------------------
264;-------------------------------------------------------------------
265;-------------------------------------------------------------------
266;-------------------------------------------------------------------
267;-------------------------------------------------------------------
268;-------------------------------------------------------------------
269;------------------------------------------------------------------------
270; 03/04/88 jwg:
271; PROCEDURE NAME: CHK_FREE_SEGMENT :
272; :
273; THIS PROCEDURE CHECKS EACH OF THE 2K BOUNDARIES IN THE 16K SEGMENT :
274; TO DETERMINE IF A ROM SEGMENT IS EMPTY. IT VERIFIES THAT NO ROM :
275; FROM A PRECEEDING ADDRESS EXTENDS INTO THIS 16K SEGMENT. ALSO THE :
276; 16K BLOCK IS CHECKED FOR THE PRESENCE OF ANY RESPONDING CARD. :
277; :
278; ENTRY: AX - CONTAINS 16K SEGMENT ADDRESS :
279; EXIT: CARRY FLAG = 0 - SEGMENT FREE :
280; CARRY FLAG = 1 - SEGMENT IN USE :
281; :
282;------------------------------------------------------------------------
283
284ROM_SCAN EQU 0AA55H
285CARD_SEL_PORT EQU 091h ; CARD SELECTED LATCH PORT
286
287
288CHK_FREE_SEGMENT PROC NEAR
289
290 PUSH AX ; Save work registers
291 PUSH BX
292 PUSH CX
293 PUSH DX
294 PUSH DI
295 PUSH ES ; Save data segment register
296 MOV BX,AX ; Save segment start address
297 MOV CX,AX ; Save in work register
298 ADD CX,0400h ; Determine End segment address of FIFE
299; MOV DX,0C000h-00100h ; Get address of start of ROM area
300 mov dx,ax ; gga
301 sub dx,0100h ; gga
302CHK_FREE_NEXT:
303 ADD DX,00100h ; Add offset to get next 2K segment
304 CMP DX,CX ; Check for past end of 16K ROM area
305 JAE CHK_FREE_OK ; IF (NC) then Exit, segment was free
306
307 ; CHECK FOR ROM BLOCK SIGNATURE
308 MOV ES,DX ; Change to new ROM segment
309 CMP ES:WORD PTR [0],ROM_SCAN; Check if a ROM module is present
310 JE CHK_FREE_SIZE ; Go check length if ROM SCAN signature
311
312 CMP BX,DX ; Check if into the target segment yet
313 JA CHK_FREE_NEXT ; Loop and check next 2K block in not
314
315 ; CHECK FOR CARD RESPONDING IN 2K
316 NOP ; Following sequence can not be traced..
317;;;;; CALL CARD_SEL_NOW ; Reset CARD SELECTED FEED BACK latch .
318 XOR DI,DI ; Clear source pointer .
319 MOV AX,0FFFFh ; Get expected floating bus pattern .
320 PUSH CX ; Save CX .
321 MOV CX,00400h ; Get count of 1 K words (2K bytes) .
322 REPE SCASW ; Check for all bits on in block ES:DI .
323 POP CX ; Recover end segment address .
324 JNE CHK_FREE_ERROR ; Exit if anything there .
325
326;;;;;; cmp rom_scan_type,family1 ; gga only do the card select check on PS2's
327;;;;;; je skip_ps2_check
328
329;;;;;; CALL CARD_SEL_NOW ; Check for a CARD SELECTED by scan .
330;;;;;; JC CHK_FREE_ERROR ; Exit (CY) if a card responded ........
331
332;;;;;;skip_ps2_check:
333 JMP CHK_FREE_NEXT ; ELSE check next 2K address
334
335CHK_FREE_SIZE: ; CHECK LENGTH INTO 16K SEGMENT
336 push cx ; gga
337 MOV AL,ES:BYTE PTR [2] ; Get ROM module length in 512 bytes
338 MOV AH,0 ; Clear high byte
339 mov cl,5 ; gga
340 SHL AX,cl ; gga convert to segment length (16 byte)
341 pop cx ; gga
342 ADD AX,DX ; Determine ending segment size
343 CMP BX,AX ; Does ROM extend into this 16K segment
344 JNB CHK_FREE_NEXT ; IF not then continue search
345
346CHK_FREE_ERROR:
347 STC ; ELSE (CY), Exit with segment not free
348CHK_FREE_OK:
349 POP ES ; restore segment register
350 POP DI
351 POP DX
352 POP CX ; restore all registers
353 POP BX
354 POP AX
355 RET ; EXIT (NC) if segment free to test
356
357CHK_FREE_SEGMENT ENDP
358
359
360;------------------------------------------------------------------------
361; 03/04/88 jwg:
362; PROCEDURE NAME: CARD_SEL_FBK :
363; :
364; THIS PROCEDURE CHECKS THE CARD SELECTED FEEDBACK LINE AND LATCH :
365; TO VERIFY THAT THIS LINE WAS ACTIVATED. METHOD IS TO CLEAR THE :
366; LATCH AND READ A LOCATION USING THE PASSED SEGMENT ADDRESS. IF :
367; ANY CARD RESPONDS THE LATCH WILL BE SET ON. :
368; :
369; NOTE: These routines can not be traced with a debug-er :
370; as VIDEO updates also set the card selected latch. :
371; :
372; ENTRY: AX - ADDRESS OF SELECTED SEGMENT :
373; :
374; EXIT: CARRY FLAG = 0 - CARD SELECTED LATCH WAS NOT SET (OFF) :
375; CARRY FLAG = 1 - CARD SELECTED LATCH WAS SET BY TEST :
376; :
377;------------------------------------------------------------------------
378
379;;;;;CARD_SEL_FBK PROC NEAR ; TEST CARD SELECTED FEED BACK
380
381;;;;; CLI ; Block interrupts during operation
382;;;;; CALL CARD_SEL_NOW ; Read current port value to clear
383;;;;; PUSH DS ; Save segment register
384;;;;; MOV DS,AX ; Set segment
385;;;;; CMP DS:BYTE PTR [0],AL ; Read first byte with dummy compare
386;;;;; POP DS ; Restore segment selector
387;;;;; CALL CARD_SEL_NOW ; Read current port value and clear
388;;;;; STI ; Enable interrupts
389;;;;; RET ; RETurn (CY)= 1 if latch set by read
390
391;;;;;CARD_SEL_FBK ENDP
392
393;------------------------------------------------------------------------
394; 03/04/88 jwg:
395; PROCEDURE NAME: CARD_SEL_NOW (CURRENT VALUE) :
396; :
397; THIS PROCEDURE READS AND RESETS THE CURRENT CARD SELECTED FEEDBACK :
398; LATCH AND RETURNS THE STATUS. :
399; :
400; NOTE: This routine can not be traced with a debug-er :
401; as VIDEO updates also set the card selected latch. :
402; :
403; ENTRY: NONE :
404; :
405; EXIT: CARRY FLAG = 0 - CARD SELECTED LATCH WAS NOT SET (OFF) :
406; CARRY FLAG = 1 - CARD SELECTED LATCH WAS SET ON WHEN READ :
407; :
408;------------------------------------------------------------------------
409
410;;;;;CARD_SEL_NOW PROC NEAR ; READ CARD SELECTED FEED BACK
411
412;;;;; PUSH AX ; Save segment address
413;;;;; IN AL,CARD_SEL_PORT ; Read current port value and clear
414;;;;; RCR AL,1 ; Move bit 0 into CY flag
415;;;;; POP AX ; Recover segment address
416;;;;; RET ; RETurn (CY)= 0 if latch set
417
418;;;;;CARD_SEL_NOW ENDP
419
420 \ No newline at end of file
HIC SVNT DRACONES