as0: Error: ../gcc-2.8.1/enquire.c, line 1075

[ShradhaNand]

Hi,
I am getting this error while installing GCC-2.8.1 on Compaq Tru64 UNIX V5.1B (Rev. 2650).....

as0: Error: ../gcc-2.8.1/enquire.c, line 1075: instruction not available in selected architecture model
itoft $0,$f2
as0: Error: ../gcc-2.8.1/enquire.c, line 1075: instruction not available in selected architecture model
itoft $0,$f1
as0: Error: ../gcc-2.8.1/enquire.c, line 1075: instruction not available in selected architecture model
ftoit $f2,$19
as0: Error: ../gcc-2.8.1/enquire.c, line 1075: instruction not available in selected architecture model
ftoit $f1,$21
as0: Error: ../gcc-2.8.1/enquire.c, line 1081: instruction not available in selected architecture model
itoft $0,$f2
as0: Error: ../gcc-2.8.1/enquire.c, line 1081: instruction not available in selected architecture model
itoft $0,$f1
..
These errors come when I do "make bootstrap".

Though configure was also not run successfully, but It got resolved when I replaced config.sub file from GCC-3.0.0. Earlier during bootstrap I got error "/gcc-2.8.1/toplev.c, line 4391: In the initializer for target_switches[18].value, "MASK_BXW" is not declared. (undeclared) = TARGET_SWITCHES;" but it also get resolved when I replaced MASK_BXW with MASK_BWX.
My machine configuration is:
"OSF1 moses V5.1 2650 alpha"

Please help me out as I am stuck with this problem.
Thanks in advance..
Shradha Nand.