Just to prove its possible :-)  The attached adds reggroups.[hc] (is 
reggroup.[ch] a better name?) and then uses it in the i386.  It 
certainly helps.  The new output looks like:

(gdb) info registers
eax            0xbffff824       -1073743836
ecx            0x0      0
edx            0xbffff82c       -1073743828
ebx            0x401d16b4       1075648180
esp            0xbffff7b0       0xbffff7b0
ebp            0xbffff7b8       0xbffff7b8
esi            0x40016b4c       1073834828
edi            0xbffff824       -1073743836
eip            0x8074b09        0x8074b09
eflags         0x282    642
cs             0x23     35
ss             0x2b     43
ds             0x2b     43
es             0x2b     43
fs             0x0      0
gs             0x0      0
orig_eax       0xffffffff       -1

(ignoring orig_eax :-) while the [very] old output looks like:

eax            0xbffff824       -1073743836
ecx            0x0      0
edx            0xbffff82c       -1073743828
ebx            0x401d16b4       1075648180
esp            0xbffff7b0       0xbffff7b0
ebp            0xbffff7b8       0xbffff7b8
esi            0x40016b4c       1073834828
edi            0xbffff824       -1073743836
eip            0x8074b09        0x8074b09
eflags         0x282    642
cs             0x23     35
ss             0x2b     43
ds             0x2b     43
es             0x2b     43
fs             0x0      0
gs             0x0      0
fctrl          0x37f    895
fstat          0x0      0
ftag           0xffff   65535
fiseg          0x23     35
fioff          0x4028f195       1076425109
foseg          0x2b     43
fooff          0x402a1758       1076500312
fop            0x1c9    457

So I think its an improvement.

I'll park this on my sysregs branch until after 5.3-branch is cut.

enjoy,
Andrew