ed@mtxinu.UUCP (01/27/87)
Description:
The MicroVAX emulation code for unimplemented instructions has
a few bugs that show themselves at the limits of "printf"s.
Also, there are numerous places where separate increment and
test instructions can be combined into one "sob" instruction.
Repeat-By:
On a uVAX-II running 4.3:
printf("%.0f\n", 0.9);
produces
0
And, in some cases, "df" will produce a capacity of 00% when
it should be 100%. Other mysterious things can happen to code
written by those strange folk who program in assembly.
Fix:
A diff of emulate.s follows:
58,61c56,57
< toarg(r8,1) # save r8 in arg1 spot
< argl(4,r8) # (4) source address == r8
< toarg(r1,4) # save r1 in arg4 spot
< tstl arg3 # (3) source length == "arg3"
---
> argl(4,r3) # (4) source address == r3
> arguw(3,r2) # (3) source length == r2
64c60
< xorb2 (r8)+,r0
---
> xorb2 (r3)+,r0
71,72c67
< decl arg3
< jneq Lcrc_loop
---
> sobgtr r2,Lcrc_loop
76,77c71
< argl(1,r8)
< argl(4,r1)
---
> clrl r1
97,99c91,92
< decl r4
< jeql Lmovtc_out
< jbr Lmovtc_loop
---
> sobgtr r4,Lmovtc_loop
> jbr Lmovtc_out
102,103c95
< decl r4
< jneq Lmovtc_2loop
---
> sobgtr r4,Lmovtc_2loop
131,132c123
< decl r4
< jneq Lmovtuc_loop
---
> sobgtr r4,Lmovtuc_loop
163,164c154
< decl r2
< jneq Lmatchc_loop
---
> sobgtr r2,Lmatchc_loop
168a159
> movl r1,r3
180d170
< argl(3,r3) # (3) table address == r3
181a172
> argl(3,r3) # (3) table address == r3
190,191c181
< decl r0
< jneq Lspanc_loop
---
> sobgtr r0,Lspanc_loop
202d191
< argl(3,r3) # (3) table address == r3
203a193
> argl(3,r3) # (3) table address == r3
212,213c202
< decl r0
< jneq Lscanc_loop
---
> sobgtr r0,Lscanc_loop
226c215
< incl r0
---
> jeql Lskpc_out # forget zero length strings
228,233c217,220
< decl r0
< jeql Lskpc_out
< cmpb (r1)+,r11
< jeql Lskpc_loop
< decl r1
< tstl r0
---
> cmpb (r1),r11
> jneq Lskpc_out
> incl r1
> sobgtr r0,Lskpc_loop
234a222
> tstl r0 # be sure of condition codes
245c233
< incl r0
---
> jeql Lskpc_out # forget zero length strings
247c235
< decl r0
---
> cmpb (r1),r11
249,252c237,238
< cmpb (r1)+,r11
< jneq Llocc_loop
< decl r1
< tstl r0
---
> incl r1
> sobgtr r0,Llocc_loop
253a240
> tstl r0 # be sure of condition codes
270,271c257
< decl r0
< jneq Lcmpc3_loop
---
> sobgtr r0,Lcmpc3_loop
295,296c281
< decl r0
< jneq Lcmpc5_loop
---
> sobgtr r0,Lcmpc5_loop
304,305c289
< decl r2
< jneq Lcmpc5_str2loop
---
> sobgtr r2,Lcmpc5_str2loop
311,312c295
< decl r0
< jneq Lcmpc5_str1loop
---
> sobgtr r0,Lcmpc5_str1loop
514,515c497
< decl r11 # while (--source length)
< jneq Laddp4_same_loop
---
> sobgtr r11,Laddp4_same_loop # while (--source length)
583,584c565
< decl r11 # loop for length of source
< jneq Lmovp_copy
---
> sobgtr r11,Lmovp_copy # loop for length of source
797,798c778
< decl r11
< jneq L200
---
> sobgtr r11,L200
830,831c810
< decl r1
< jneq Le_fill_loop
---
> sobgtr r1,Le_fill_loop
856,857c835
< decl r1
< jneq L214
---
> sobgtr r1,L214
885,886c863
< decl r1
< jneq L221
---
> sobgtr r1,L221
901a879
> # arg2 holds "even or odd" destination length
918,919c896,901
< L245: # r3<0> counts digits going into destination
< bisl2 $1,r3 # and is flip-flop for which nibble to
---
> L245:
> clrl arg2 # arg2 is 1 if dstlen is even, 0 if odd
> blbs r3,L246
> incl arg2
> bisl2 $1,r3 # r3<0> counts digits going into destination
> L246: # and is flip-flop for which nibble to
946,948c928,929
< decl r3 # move to next nibble in destination, but
< jneq L258 # don't go beyond the end.
< incl r3
---
> sobgtr r3,L258 # move to next nibble in destination, but
> incl r3 # don't go beyond the end.
959c940
< jeql Lashp_sethigh
---
> jeql Lashp_round
981,984c962,966
< jgeq Lashp_noovfl # if we've moved passed destination limits
< clrl r3 # test the result for possible overflow
< tstl arg5 # ignore zero nibbles
< jeql L265 # if the nibble was non-zero, overflow
---
> cmpl r3,arg2 # if we've moved passed destination limits
> jgeq Lashp_noovfl # test the result for possible overflow
> movl arg2,r3 # ignore zero nibbles
> tstl arg5 # if the nibble was non-zero, overflow
> jeql L265
991,992c973
< decl r6
< insv arg5,$0,$4,(r6)
---
> movb arg5,-(r6)
994,995c975
< decl r10 # loop for length of source
< jneq Lashp_shloop
---
> sobgtr r10,Lashp_shloop # loop for length of source
997,1000c977,985
< Lashp_sethigh:
< jlbc r3,L266 # if we haven't set the high nibble,
< insv r2,$4,$4,(r6) # carry the round into the high nibble
< clrl r2
---
> Lashp_round:
> tstl r2 # take care of round out of high nibble
> jeql Lashp_zeroround
> decl r3
> cmpl r3,arg2 # if we've moved passed destination limits
> jlss Lashp_overfl # then overflow
> jlbs r3,L266
> insv arg5,$4,$4,(r6) # put the round into destination (high or low)
> jbr Lashp_zeroround
1001a987,989
> movb arg5,-(r6)
>
> Lashp_zeroround:
1008,1009c996
< cvtlb r2,-(r6) # fill up MSNs of destination with carry or zero
< clrl r2
---
> clrb -(r6) # fill up MSNs of destination with zeros
1013,1014d999
< tstl r2 # if carry beyond destination, overflow
< jneq Lashp_overfl
1102,1103c1087
< decl r11
< jneq Lcvtpl_loop
---
> sobgtr r11,Lcvtpl_loop
--
Ed Gould mt Xinu, 2560 Ninth St., Berkeley, CA 94710 USA
{ucbvax,decvax}!mtxinu!ed +1 415 644 0146
"A man of quality is not threatened by a woman of equality."