source: rtems/bsps/m68k/shared/fpsp/bugfix.S @ d7d66d7

5
Last change on this file since d7d66d7 was 3cf2bf63, checked in by Sebastian Huber <sebastian.huber@…>, on 03/26/18 at 10:17:06

bsps/m68k: Move fpsp support to bsps

This patch is a part of the BSP source reorganization.

Update #3285.

  • Property mode set to 100644
File size: 14.1 KB
Line 
1#include "fpsp-namespace.h"
2//
3//
4//      bugfix.sa 3.2 1/31/91
5//
6//      This file contains workarounds for bugs in the 040
7//      relating to the Floating-Point Software Package (FPSP)
8//
9//      Fixes for bugs: 1238
10//
11//      Bug: 1238
12//
13//
14//    /* The following dirty_bit clear should be left in
15//     * the handler permanently to improve throughput.
16//     * The dirty_bits are located at bits [23:16] in
17//     * longword $08 in the busy frame $4x60.  Bit 16
18//     * corresponds to FP0, bit 17 corresponds to FP1,
19//     * and so on.
20//     */
21//    if  (E3_exception_just_serviced)   {
22//         dirty_bit[cmdreg3b[9:7]] = 0;
23//         }
24//
25//    if  (fsave_format_version != $40)  {goto NOFIX}
26//
27//    if !(E3_exception_just_serviced)   {goto NOFIX}
28//    if  (cupc == 0000000)              {goto NOFIX}
29//    if  ((cmdreg1b[15:13] != 000) &&
30//         (cmdreg1b[15:10] != 010001))  {goto NOFIX}
31//    if (((cmdreg1b[15:13] != 000) || ((cmdreg1b[12:10] != cmdreg2b[9:7]) &&
32//                                    (cmdreg1b[12:10] != cmdreg3b[9:7]))  ) &&
33//       ((cmdreg1b[ 9: 7] != cmdreg2b[9:7]) &&
34//        (cmdreg1b[ 9: 7] != cmdreg3b[9:7])) )  {goto NOFIX}
35//
36//    /* Note: for 6d43b or 8d43b, you may want to add the following code
37//     * to get better coverage.  (If you do not insert this code, the part
38//     * won't lock up; it will simply get the wrong answer.)
39//     * Do NOT insert this code for 10d43b or later parts.
40//     *
41//     *  if (fpiarcu == integer stack return address) {
42//     *       cupc = 0000000;
43//     *       goto NOFIX;
44//     *       }
45//     */
46//
47//    if (cmdreg1b[15:13] != 000)   {goto FIX_OPCLASS2}
48//    FIX_OPCLASS0:
49//    if (((cmdreg1b[12:10] == cmdreg2b[9:7]) ||
50//       (cmdreg1b[ 9: 7] == cmdreg2b[9:7])) &&
51//      (cmdreg1b[12:10] != cmdreg3b[9:7]) &&
52//      (cmdreg1b[ 9: 7] != cmdreg3b[9:7]))  {  /* xu conflict only */
53//      /* We execute the following code if there is an
54//         xu conflict and NOT an nu conflict */
55//
56//      /* first save some values on the fsave frame */
57//      stag_temp     = STAG[fsave_frame];
58//      cmdreg1b_temp = CMDREG1B[fsave_frame];
59//      dtag_temp     = DTAG[fsave_frame];
60//      ete15_temp    = ETE15[fsave_frame];
61//
62//      CUPC[fsave_frame] = 0000000;
63//      FRESTORE
64//      FSAVE
65//
66//      /* If the xu instruction is exceptional, we punt.
67//       * Otherwise, we would have to include OVFL/UNFL handler
68//       * code here to get the correct answer.
69//       */
70//      if (fsave_frame_format == $4060) {goto KILL_PROCESS}
71//
72//      fsave_frame = /* build a long frame of all zeros */
73//      fsave_frame_format = $4060;  /* label it as long frame */
74//
75//      /* load it with the temps we saved */
76//      STAG[fsave_frame]     =  stag_temp;
77//      CMDREG1B[fsave_frame] =  cmdreg1b_temp;
78//      DTAG[fsave_frame]     =  dtag_temp;
79//      ETE15[fsave_frame]    =  ete15_temp;
80//
81//      /* Make sure that the cmdreg3b dest reg is not going to
82//       * be destroyed by a FMOVEM at the end of all this code.
83//       * If it is, you should move the current value of the reg
84//       * onto the stack so that the reg will loaded with that value.
85//       */
86//
87//      /* All done.  Proceed with the code below */
88//    }
89//
90//    etemp  = FP_reg_[cmdreg1b[12:10]];
91//    ete15  = ~ete14;
92//    cmdreg1b[15:10] = 010010;
93//    clear(bug_flag_procIDxxxx);
94//    FRESTORE and return;
95//
96//
97//    FIX_OPCLASS2:
98//    if ((cmdreg1b[9:7] == cmdreg2b[9:7]) &&
99//      (cmdreg1b[9:7] != cmdreg3b[9:7]))  {  /* xu conflict only */
100//      /* We execute the following code if there is an
101//         xu conflict and NOT an nu conflict */
102//
103//      /* first save some values on the fsave frame */
104//      stag_temp     = STAG[fsave_frame];
105//      cmdreg1b_temp = CMDREG1B[fsave_frame];
106//      dtag_temp     = DTAG[fsave_frame];
107//      ete15_temp    = ETE15[fsave_frame];
108//      etemp_temp    = ETEMP[fsave_frame];
109//
110//      CUPC[fsave_frame] = 0000000;
111//      FRESTORE
112//      FSAVE
113//
114//
115//      /* If the xu instruction is exceptional, we punt.
116//       * Otherwise, we would have to include OVFL/UNFL handler
117//       * code here to get the correct answer.
118//       */
119//      if (fsave_frame_format == $4060) {goto KILL_PROCESS}
120//
121//      fsave_frame = /* build a long frame of all zeros */
122//      fsave_frame_format = $4060;  /* label it as long frame */
123//
124//      /* load it with the temps we saved */
125//      STAG[fsave_frame]     =  stag_temp;
126//      CMDREG1B[fsave_frame] =  cmdreg1b_temp;
127//      DTAG[fsave_frame]     =  dtag_temp;
128//      ETE15[fsave_frame]    =  ete15_temp;
129//      ETEMP[fsave_frame]    =  etemp_temp;
130//
131//      /* Make sure that the cmdreg3b dest reg is not going to
132//       * be destroyed by a FMOVEM at the end of all this code.
133//       * If it is, you should move the current value of the reg
134//       * onto the stack so that the reg will loaded with that value.
135//       */
136//
137//      /* All done.  Proceed with the code below */
138//    }
139//
140//    if (etemp_exponent == min_sgl)   etemp_exponent = min_dbl;
141//    if (etemp_exponent == max_sgl)   etemp_exponent = max_dbl;
142//    cmdreg1b[15:10] = 010101;
143//    clear(bug_flag_procIDxxxx);
144//    FRESTORE and return;
145//
146//
147//    NOFIX:
148//    clear(bug_flag_procIDxxxx);
149//    FRESTORE and return;
150//
151
152
153//              Copyright (C) Motorola, Inc. 1990
154//                      All Rights Reserved
155//
156//      THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA
157//      The copyright notice above does not evidence any
158//      actual or intended publication of such source code.
159
160//BUGFIX    idnt    2,1 | Motorola 040 Floating Point Software Package
161
162        |section        8
163
164#include "fpsp.defs"
165
166        |xref   fpsp_fmt_error
167
168        .global b1238_fix
169b1238_fix:
170//
171// This code is entered only on completion of the handling of an
172// nu-generated ovfl, unfl, or inex exception.  If the version
173// number of the fsave is not $40, this handler is not necessary.
174// Simply branch to fix_done and exit normally.
175//
176        cmpib   #VER_40,4(%a7)
177        bne     fix_done
178//
179// Test for cu_savepc equal to zero.  If not, this is not a bug
180// #1238 case.
181//
182        moveb   CU_SAVEPC(%a6),%d0
183        andib   #0xFE,%d0
184        beq     fix_done        //if zero, this is not bug #1238
185
186//
187// Test the register conflict aspect.  If opclass0, check for
188// cu src equal to xu dest or equal to nu dest.  If so, go to
189// op0.  Else, or if opclass2, check for cu dest equal to
190// xu dest or equal to nu dest.  If so, go to tst_opcl.  Else,
191// exit, it is not the bug case.
192//
193// Check for opclass 0.  If not, go and check for opclass 2 and sgl.
194//
195        movew   CMDREG1B(%a6),%d0
196        andiw   #0xE000,%d0             //strip all but opclass
197        bne     op2sgl                  //not opclass 0, check op2
198//
199// Check for cu and nu register conflict.  If one exists, this takes
200// priority over a cu and xu conflict.
201//
202        bfextu  CMDREG1B(%a6){#3:#3},%d0        //get 1st src
203        bfextu  CMDREG3B(%a6){#6:#3},%d1        //get 3rd dest
204        cmpb    %d0,%d1
205        beqs    op0                     //if equal, continue bugfix
206//
207// Check for cu dest equal to nu dest.  If so, go and fix the
208// bug condition.  Otherwise, exit.
209//
210        bfextu  CMDREG1B(%a6){#6:#3},%d0        //get 1st dest
211        cmpb    %d0,%d1                 //cmp 1st dest with 3rd dest
212        beqs    op0                     //if equal, continue bugfix
213//
214// Check for cu and xu register conflict.
215//
216        bfextu  CMDREG2B(%a6){#6:#3},%d1        //get 2nd dest
217        cmpb    %d0,%d1                 //cmp 1st dest with 2nd dest
218        beqs    op0_xu                  //if equal, continue bugfix
219        bfextu  CMDREG1B(%a6){#3:#3},%d0        //get 1st src
220        cmpb    %d0,%d1                 //cmp 1st src with 2nd dest
221        beq     op0_xu
222        bne     fix_done                //if the reg checks fail, exit
223//
224// We have the opclass 0 situation.
225//
226op0:
227        bfextu  CMDREG1B(%a6){#3:#3},%d0        //get source register no
228        movel   #7,%d1
229        subl    %d0,%d1
230        clrl    %d0
231        bsetl   %d1,%d0
232        fmovemx %d0,ETEMP(%a6)          //load source to ETEMP
233
234        moveb   #0x12,%d0
235        bfins   %d0,CMDREG1B(%a6){#0:#6}        //opclass 2, extended
236//
237//      Set ETEMP exponent bit 15 as the opposite of ete14
238//
239        btst    #6,ETEMP_EX(%a6)                //check etemp exponent bit 14
240        beq     setete15
241        bclr    #etemp15_bit,STAG(%a6)
242        bra     finish
243setete15:
244        bset    #etemp15_bit,STAG(%a6)
245        bra     finish
246
247//
248// We have the case in which a conflict exists between the cu src or
249// dest and the dest of the xu.  We must clear the instruction in
250// the cu and restore the state, allowing the instruction in the
251// xu to complete.  Remember, the instruction in the nu
252// was exceptional, and was completed by the appropriate handler.
253// If the result of the xu instruction is not exceptional, we can
254// restore the instruction from the cu to the frame and continue
255// processing the original exception.  If the result is also
256// exceptional, we choose to kill the process.
257//
258//      Items saved from the stack:
259//
260//              $3c stag     - L_SCR1
261//              $40 cmdreg1b - L_SCR2
262//              $44 dtag     - L_SCR3
263//
264// The cu savepc is set to zero, and the frame is restored to the
265// fpu.
266//
267op0_xu:
268        movel   STAG(%a6),L_SCR1(%a6)
269        movel   CMDREG1B(%a6),L_SCR2(%a6)
270        movel   DTAG(%a6),L_SCR3(%a6)
271        andil   #0xe0000000,L_SCR3(%a6)
272        moveb   #0,CU_SAVEPC(%a6)
273        movel   (%a7)+,%d1              //save return address from bsr
274        frestore (%a7)+
275        fsave   -(%a7)
276//
277// Check if the instruction which just completed was exceptional.
278//
279        cmpw    #0x4060,(%a7)
280        beq     op0_xb
281//
282// It is necessary to isolate the result of the instruction in the
283// xu if it is to fp0 - fp3 and write that value to the USER_FPn
284// locations on the stack.  The correct destination register is in
285// cmdreg2b.
286//
287        bfextu  CMDREG2B(%a6){#6:#3},%d0        //get dest register no
288        cmpil   #3,%d0
289        bgts    op0_xi
290        beqs    op0_fp3
291        cmpil   #1,%d0
292        blts    op0_fp0
293        beqs    op0_fp1
294op0_fp2:
295        fmovemx %fp2-%fp2,USER_FP2(%a6)
296        bras    op0_xi
297op0_fp1:
298        fmovemx %fp1-%fp1,USER_FP1(%a6)
299        bras    op0_xi
300op0_fp0:
301        fmovemx %fp0-%fp0,USER_FP0(%a6)
302        bras    op0_xi
303op0_fp3:
304        fmovemx %fp3-%fp3,USER_FP3(%a6)
305//
306// The frame returned is idle.  We must build a busy frame to hold
307// the cu state information and setup etemp.
308//
309op0_xi:
310        movel   #22,%d0         //clear 23 lwords
311        clrl    (%a7)
312op0_loop:
313        clrl    -(%a7)
314        dbf     %d0,op0_loop
315        movel   #0x40600000,-(%a7)
316        movel   L_SCR1(%a6),STAG(%a6)
317        movel   L_SCR2(%a6),CMDREG1B(%a6)
318        movel   L_SCR3(%a6),DTAG(%a6)
319        moveb   #0x6,CU_SAVEPC(%a6)
320        movel   %d1,-(%a7)              //return bsr return address
321        bfextu  CMDREG1B(%a6){#3:#3},%d0        //get source register no
322        movel   #7,%d1
323        subl    %d0,%d1
324        clrl    %d0
325        bsetl   %d1,%d0
326        fmovemx %d0,ETEMP(%a6)          //load source to ETEMP
327
328        moveb   #0x12,%d0
329        bfins   %d0,CMDREG1B(%a6){#0:#6}        //opclass 2, extended
330//
331//      Set ETEMP exponent bit 15 as the opposite of ete14
332//
333        btst    #6,ETEMP_EX(%a6)                //check etemp exponent bit 14
334        beq     op0_sete15
335        bclr    #etemp15_bit,STAG(%a6)
336        bra     finish
337op0_sete15:
338        bset    #etemp15_bit,STAG(%a6)
339        bra     finish
340
341//
342// The frame returned is busy.  It is not possible to reconstruct
343// the code sequence to allow completion.  We will jump to
344// fpsp_fmt_error and allow the kernel to kill the process.
345//
346op0_xb:
347        jmp     fpsp_fmt_error
348
349//
350// Check for opclass 2 and single size.  If not both, exit.
351//
352op2sgl:
353        movew   CMDREG1B(%a6),%d0
354        andiw   #0xFC00,%d0             //strip all but opclass and size
355        cmpiw   #0x4400,%d0             //test for opclass 2 and size=sgl
356        bne     fix_done                //if not, it is not bug 1238
357//
358// Check for cu dest equal to nu dest or equal to xu dest, with
359// a cu and nu conflict taking priority an nu conflict.  If either,
360// go and fix the bug condition.  Otherwise, exit.
361//
362        bfextu  CMDREG1B(%a6){#6:#3},%d0        //get 1st dest
363        bfextu  CMDREG3B(%a6){#6:#3},%d1        //get 3rd dest
364        cmpb    %d0,%d1                 //cmp 1st dest with 3rd dest
365        beq     op2_com                 //if equal, continue bugfix
366        bfextu  CMDREG2B(%a6){#6:#3},%d1        //get 2nd dest
367        cmpb    %d0,%d1                 //cmp 1st dest with 2nd dest
368        bne     fix_done                //if the reg checks fail, exit
369//
370// We have the case in which a conflict exists between the cu src or
371// dest and the dest of the xu.  We must clear the instruction in
372// the cu and restore the state, allowing the instruction in the
373// xu to complete.  Remember, the instruction in the nu
374// was exceptional, and was completed by the appropriate handler.
375// If the result of the xu instruction is not exceptional, we can
376// restore the instruction from the cu to the frame and continue
377// processing the original exception.  If the result is also
378// exceptional, we choose to kill the process.
379//
380//      Items saved from the stack:
381//
382//              $3c stag     - L_SCR1
383//              $40 cmdreg1b - L_SCR2
384//              $44 dtag     - L_SCR3
385//              etemp        - FP_SCR2
386//
387// The cu savepc is set to zero, and the frame is restored to the
388// fpu.
389//
390op2_xu:
391        movel   STAG(%a6),L_SCR1(%a6)
392        movel   CMDREG1B(%a6),L_SCR2(%a6)
393        movel   DTAG(%a6),L_SCR3(%a6)
394        andil   #0xe0000000,L_SCR3(%a6)
395        moveb   #0,CU_SAVEPC(%a6)
396        movel   ETEMP(%a6),FP_SCR2(%a6)
397        movel   ETEMP_HI(%a6),FP_SCR2+4(%a6)
398        movel   ETEMP_LO(%a6),FP_SCR2+8(%a6)
399        movel   (%a7)+,%d1              //save return address from bsr
400        frestore (%a7)+
401        fsave   -(%a7)
402//
403// Check if the instruction which just completed was exceptional.
404//
405        cmpw    #0x4060,(%a7)
406        beq     op2_xb
407//
408// It is necessary to isolate the result of the instruction in the
409// xu if it is to fp0 - fp3 and write that value to the USER_FPn
410// locations on the stack.  The correct destination register is in
411// cmdreg2b.
412//
413        bfextu  CMDREG2B(%a6){#6:#3},%d0        //get dest register no
414        cmpil   #3,%d0
415        bgts    op2_xi
416        beqs    op2_fp3
417        cmpil   #1,%d0
418        blts    op2_fp0
419        beqs    op2_fp1
420op2_fp2:
421        fmovemx %fp2-%fp2,USER_FP2(%a6)
422        bras    op2_xi
423op2_fp1:
424        fmovemx %fp1-%fp1,USER_FP1(%a6)
425        bras    op2_xi
426op2_fp0:
427        fmovemx %fp0-%fp0,USER_FP0(%a6)
428        bras    op2_xi
429op2_fp3:
430        fmovemx %fp3-%fp3,USER_FP3(%a6)
431//
432// The frame returned is idle.  We must build a busy frame to hold
433// the cu state information and fix up etemp.
434//
435op2_xi:
436        movel   #22,%d0         //clear 23 lwords
437        clrl    (%a7)
438op2_loop:
439        clrl    -(%a7)
440        dbf     %d0,op2_loop
441        movel   #0x40600000,-(%a7)
442        movel   L_SCR1(%a6),STAG(%a6)
443        movel   L_SCR2(%a6),CMDREG1B(%a6)
444        movel   L_SCR3(%a6),DTAG(%a6)
445        moveb   #0x6,CU_SAVEPC(%a6)
446        movel   FP_SCR2(%a6),ETEMP(%a6)
447        movel   FP_SCR2+4(%a6),ETEMP_HI(%a6)
448        movel   FP_SCR2+8(%a6),ETEMP_LO(%a6)
449        movel   %d1,-(%a7)
450        bra     op2_com
451
452//
453// We have the opclass 2 single source situation.
454//
455op2_com:
456        moveb   #0x15,%d0
457        bfins   %d0,CMDREG1B(%a6){#0:#6}        //opclass 2, double
458
459        cmpw    #0x407F,ETEMP_EX(%a6)   //single +max
460        bnes    case2
461        movew   #0x43FF,ETEMP_EX(%a6)   //to double +max
462        bra     finish
463case2:
464        cmpw    #0xC07F,ETEMP_EX(%a6)   //single -max
465        bnes    case3
466        movew   #0xC3FF,ETEMP_EX(%a6)   //to double -max
467        bra     finish
468case3:
469        cmpw    #0x3F80,ETEMP_EX(%a6)   //single +min
470        bnes    case4
471        movew   #0x3C00,ETEMP_EX(%a6)   //to double +min
472        bra     finish
473case4:
474        cmpw    #0xBF80,ETEMP_EX(%a6)   //single -min
475        bne     fix_done
476        movew   #0xBC00,ETEMP_EX(%a6)   //to double -min
477        bra     finish
478//
479// The frame returned is busy.  It is not possible to reconstruct
480// the code sequence to allow completion.  fpsp_fmt_error causes
481// an fline illegal instruction to be executed.
482//
483// You should replace the jump to fpsp_fmt_error with a jump
484// to the entry point used to kill a process.
485//
486op2_xb:
487        jmp     fpsp_fmt_error
488
489//
490// Enter here if the case is not of the situations affected by
491// bug #1238, or if the fix is completed, and exit.
492//
493finish:
494fix_done:
495        rts
496
497        |end
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