> Module Name: src
> Committed By: nat
> Date: Wed Apr 9 00:04:41 UTC 2025
>
> Modified Files:
> src/sys/arch/m68k/m68k: fpu.c
>
> Log Message:
> Add workaround for fpu test for kernels defined with M68040.
>
> This is to accomodate kernels built without the -mlcfix option passed to
> gas(1).
>
> As discussed on tech-kern - It would be remiss of me otherwize.
Do you have a certain scenario that the write-pending could happen
just before F-line Unimplemented Exception by the fnop in fpu_probe()?
On hp300 objdump -d GENERIC/netbsd shows:
000146a4 <fpu_probe>:
struct fpframe fpframe;
label_t faultbuf;
uint8_t b;
146a4: 4e56 fe80 linkw %fp,#-384
146a8: 2f02 movel %d2,%sp@-
nofault = (int *)&faultbuf;
146aa: 41ee fe80 lea %fp@(-384),%a0
146ae: 23c8 002d eb00 movel %a0,2deb00 <nofault>
if (setjmp(&faultbuf)) {
146b4: 486e fe80 pea %fp@(-384)
146b8: 4eb9 0002 029c jsr 2029c <setjmp>
146be: 588f addql #4,%sp
146c0: 4a80 tstl %d0
146c2: 670a beqs 146ce <fpu_probe+0x2a>
nofault = (int *)0;
146c4: 42b9 002d eb00 clrl 2deb00 <nofault>
146ca: 4280 clrl %d0
return FPU_NONE;
146cc: 6054 bras 14722 <fpu_probe+0x7e>
}
__asm("fnop");
146ce: f280 0000 fnop
nofault = NULL;
146d2: 42b9 002d eb00 clrl 2deb00 <nofault>
if (cputype == CPU_68060)
146d8: 2039 002c 5018 movel 2c5018 <cputype>,%d0
146de: 7203 moveq #3,%d1
146e0: b280 cmpl %d0,%d1
return FPU_68060;
146e2: 6730 beqs 14714 <fpu_probe+0x70>
if (cputype == CPU_68040)
146e4: 5580 subql #2,%d0
return FPU_68040;
146e6: 6730 beqs 14718 <fpu_probe+0x74>
__asm("fsave %0@" : : "a" (&fpframe) : "memory");
146e8: 41ee febc lea %fp@(-324),%a0
146ec: f310 fsave %a0@
b = fpframe.fpf_fsize;
146ee: 142e febd moveb %fp@(-323),%d2
fpframe.fpf_null = 0;
146f2: 42ae febc clrl %fp@(-324)
fpframe.fpf_idle.fpf_ccr = 0;
146f6: 426e fec0 clrw %fp@(-320)
m68881_restore(&fpframe);
146fa: 2f08 movel %a0,%sp@-
146fc: 4eb9 0000 1bd6 jsr 1bd6 <m68881_restore>
14702: 588f addql #4,%sp
if (b == 0x18)
14704: 0c02 0018 cmpib #24,%d2
return FPU_68881;
14708: 6712 beqs 1471c <fpu_probe+0x78>
if (b == 0x38)
1470a: 0c02 0038 cmpib #56,%d2
return FPU_68882;
1470e: 6710 beqs 14720 <fpu_probe+0x7c>
return FPU_UNKNOWN;
14710: 7005 moveq #5,%d0
14712: 600e bras 14722 <fpu_probe+0x7e>
14714: 7004 moveq #4,%d0
14716: 600a bras 14722 <fpu_probe+0x7e>
14718: 7003 moveq #3,%d0
1471a: 6006 bras 14722 <fpu_probe+0x7e>
1471c: 7001 moveq #1,%d0
1471e: 6002 bras 14722 <fpu_probe+0x7e>
14720: 7002 moveq #2,%d0
14722: 242e fe7c movel %fp@(-388),%d2
14726: 4e5e unlk %fp
14728: 4e75 rts
---
Izumi Tsutsui
