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[smlnj] Diff of /sml/trunk/NOTES/HISTORY
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Diff of /sml/trunk/NOTES/HISTORY

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revision 1171, Fri Mar 22 20:41:43 2002 UTC revision 1201, Fri May 17 20:48:38 2002 UTC
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13  Description:  Description:
14    
15  ----------------------------------------------------------------------  ----------------------------------------------------------------------
16    Name: Matthias Blume
17    Date: 2002/05/17 16:49:00 EDT
18    Tag: blume-20020517-controls
19    Description:
20    
21    0. John Reppy made several modifications to the SML/NJ library.
22       In particular, there is a shiny new controls-lib.cm.
23    
24    1. Pushed new controls interface through compiler so that everything
25       compiles again.
26    
27    2. Added FormatComb and FORMAT_COMB to the CML version of the
28       SML/NJ library (so that CML compiles again).
29    
30    3. Modified init scripts because XXX_DEFAULT environment variables
31       are no longer with us.  (Boot-time initialization is now done
32       using the same environment variables that are also used for
33       startup-time initialization of controls.)
34    
35    ----------------------------------------------------------------------
36    Name: Lal George
37    Date: 2002/05/15 09:20:10 EDT
38    Tag: george-20020515-pseudo-op-decls
39    Description:
40    
41            All pseudo-ops emitted before the first segment declaration
42    such as TEXT, DATA, and BSS directives are assumed to be global
43    declarations and are emitted first in the assembly file. This is
44    useful in a number of situations where one has pseudo-ops that are not
45    specific to any segment, and also works around the constraint that one
46    cannot have client pseudo-ops in the TEXT segment.
47    
48            Because no segment is associated with these declarations it is
49    an error to allocate any space or objects before the first segment
50    directive and an exception will be raised. However, we cannot make
51    this check for client pseudo-ops.
52    
53            These top level declarations are a field in the CFG graph_info.
54    In theory you can continue to add to this field after the CFG has been
55    built -- provided you know what you are doing;-)
56    
57    ----------------------------------------------------------------------
58    Name: Matthias Blume
59    Date: 2002/05/13 16:40:00 EDT
60    Tag: blume-20020513-pp-etc
61    Description:
62    
63    A few minor bugfixes:
64    
65      - Stopgap measure for bug recently reported by Elsa Gunter (ppDec).
66        (Bogus printouts for redefined bindings still occur.  Compiler
67        bug should no longer occur now.  We need to redo the prettyprinter
68        from scratch.)
69    
70      - CM pathname printer now also adds escape sequences for ( and )
71    
72      - commend and docu fixes for ml-nlffi
73    
74    ----------------------------------------------------------------------
75    Name: Matthias Blume
76    Date: 2002/05/10 16:40:00 EDT
77    Tag: blume-20020510-erg-textio
78    Description:
79    
80    Applied the following bugfix provided by Emden Gansner:
81    
82        Output is corrupted when outputSubstr is used rather than output.
83    
84        The problem occurs when a substring
85    
86            ss = (s, dataStart, dataLen)
87    
88        where dataStart > 0, fills a stream buffer with avail bytes left.
89        avail bytes of s, starting at index dataStart, are copied into the
90        buffer, the buffer is flushed, and then the remaining dataLen-avail
91        bytes of ss are copied into the beginning of the buffer. Instead of
92        starting this copy at index dataStart+avail in s, the current code
93        starts the copy at index avail.
94    
95        Fix:
96        In text-io-fn.sml, change line 695 from
97             val needsFlush = copyVec(v, avail, dataLen-avail, buf, 0)
98        to
99             val needsFlush = copyVec(v, dataStart+avail, dataLen-avail, buf, 0)
100    
101    ----------------------------------------------------------------------
102    Name: Matthias Blume
103    Date: 2002/04/12 13:55:00 EDT
104    Tag: blume-20020412-assyntax
105    Description:
106    
107    1. Grabbed newer assyntax.h from the XFree86 project.
108    2. Fiddled with how to compile X86.prim.asm without warnings.
109    3. (Very) Minor cleanup in CM.
110    
111    ----------------------------------------------------------------------
112    Name: Matthias Blume
113    Date: 2002/04/01 (no joke!) 17:07:00 EST
114    Tag: blume-20020401-x86div
115    Description:
116    
117    Added full support for div/mod/rem/quot on the x86, using the machine
118    instruction's two results (without clumsily recomputing the remainder)
119    directly where appropriate.
120    
121    Some more extensive power-of-two support was added to the x86 instruction
122    selector (avoiding expensive divs, mods, and muls where they can be
123    replaced with cheaper shifts and masks).  However, this sort of thing
124    ought to be done earlier, e.g., within the CPS optimizer so that
125    all architectures benefit from it.
126    
127    The compiler compiles to a fixed point, but changes might be somewhat
128    fragile nevertheless.  Please, report any strange things that you might
129    see wrt. div/mod/quot/rem...
130    
131    ----------------------------------------------------------------------
132    Name: Matthias Blume
133    Date: 2002/03/29 17:22:00
134    Tag: blume-20020329-div
135    Description:
136    
137    Fixed my broken div/mod logic.  Unfortunately, this means that the
138    inline code for div/mod now has one more comparison than before.
139    Fast paths (quotient > 0 or remainder = 0) are not affected, though.
140    The problem was with quotient = 0, because that alone does not tell
141    us which way the rounding went.  One then has to look at whether
142    remainder and divisor have the same sign...  :(
143    
144    Anyway, I replaced the bootfiles with fresh ones...
145    
146    ----------------------------------------------------------------------
147    Name: Matthias Blume
148    Date: 2002/03/29 14:10:00 EST
149    Tag: blume-20020329-inlprims
150    Description:
151    
152    NEW BOOTFILES!!!    Version number bumped to 110.39.3.
153    
154    Primops have changed. This means that the bin/boot-file formats have
155    changed as well.
156    
157    To make sure that there is no confusion, I made a new version.
158    
159    
160    CHANGES:
161    
162    * removed REMT from mltree (remainder should never overflow).
163    
164    * added primops to deal with divisions of all flavors to the frontend
165    
166    * handled these primops all the way through so they map to their respective
167      MLRISC support
168    
169    * used these primops in the implementation of Int, Int32, Word, Word32
170    
171    * removed INLDIV, INLMOD, and INLREM as they are no longer necessary
172    
173    * parameterized INLMIN, INLMAX, and INLABS by a numkind
174    
175    * translate.sml now deals with all flavors of INL{MIN,MAX,ABS}, including
176      floating point
177    
178    * used INL{MIN,MAX,ABS} in the implementation of Int, Int32, Word, Word32,
179      and Real (but Real.abs maps to a separate floating-point-only primop)
180    
181    
182    TODO items:
183    
184    * Hacked Alpha32 instruction selection, disabling the selection of REMx
185      instructions because the machine instruction encoder cannot handle
186      them.  (Hppa, PPC, and Sparc instruction selection did not handle
187      REM in the first place, and REM is supported by the x86 machine coder.)
188    
189    * Handle DIV and MOD with DIV_TO_NEGINF directly in the x86 instruction
190      selection phase.  (The two can be streamlined because the hardware
191      delivers both quotient and remainder at the same time anyway.)
192    
193    * Think about what to do with "valOf(Int32.minInt) div ~1" and friends.
194      (Currently the behavior is inconsistent both across architectures and
195      wrt. the draft Basis spec.)
196    
197    * Word8 should eventually be handled natively, too.
198    
199    * There seems to be one serious bug in mltree-gen.sml.  It appears, though,
200      as if there currently is no execution path that could trigger it in
201      SML/NJ.  (The assumptions underlying functions arith and promotable do not
202      hold for things like multiplication and division.)
203    
204    ----------------------------------------------------------------------
205    Name: Matthias Blume
206    Date: 2002/03/27 16:27:00 EST
207    Tag: blume-20020327-mlrisc-divisions
208    Description:
209    
210    Added support for all four division operations (ML's div, mod, quot,
211    and rem) to MLRISC.  In the course of doing so, I also rationalized
212    the naming (no more annoying switch-around of DIV and QUOT), by
213    parameterizing the operation by div_rounding_mode (which can be either
214    DIV_TO_ZERO or DIV_TO_NEGINF).
215    
216    The generic MLTreeGen functor takes care of compiling all four
217    operations down to only round-to-zero div.
218    
219    Missing pieces:
220    
221      * Doing something smarter than relying on MLTreeGen on architectures
222        like, e.g., the x86 where hardware division delivers both quotient and
223        remainder at the same time.  With this, the implementation of the
224        round-to-neginf operations could be further streamlined.
225    
226      * Remove inlining support for div/mod/rem from the frontend and replace it
227        with primops that get carried through to the backend.  Do this for all
228        int and word types.
229    
230    ----------------------------------------------------------------------
231    Name: Matthias Blume
232    Date: 2002/03/25 17:25:00 EST
233    Tag: blume-20020325-divmod
234    Description:
235    
236    I improved (hopefully without breaking them) the implementation of Int.div,
237    Int.mod, and Int.rem.   For this, the code in translate.sml now takes
238    advantage of the following observations:
239    
240      Let  q = x quot y      r = x rem y
241           d = x div  y      m = x mod y
242    
243    where "quot" is the round-to-zero version of integer division that
244    hardware usually provides.  Then we have:
245    
246         r = x - q * y        where neither the * nor the - will overflow
247         d = if q >= 0 orelse x = q * y then q else q - 1
248                              where neither the * nor the - will overflow
249         m = if q >= 0 orelse r = 0 then r else r + y
250                              where the + will not overflow
251    
252    This results in substantial simplification of the generated code.
253    The following table shows the number of CFG nodes and edges generated
254    for
255            fun f (x, y) = x OPER y
256            (* with OPER \in div, mod, quot, rem *)
257    
258    
259        OPER | nodes(old) | edges(old) | nodes(new) | edges(new)
260        --------------------------------------------------------
261         div |         24 |         39 |         12 |         16
262         mod |         41 |         71 |         12 |         16
263        quot |          8 |         10 |          8 |         10
264         rem |         10 |         14 |          8 |         10
265    
266    
267    ----------------------------------------------------------------------
268    Name: Matthias Blume
269    Date: 2002/03/25 22:06:00 EST
270    Tag: blume-20020325-cprotobug
271    Description:
272    
273    Fixed a bug in cproto (c prototype decoder).
274    
275    ----------------------------------------------------------------------
276    Name: Matthias Blume
277    Date: 2002/03/25 16:00:00 EST
278    Tag: blume-20020325-raw-primops
279    Description:
280    
281    I did some cleanup to Allen's new primop code and
282    replaced yesterday's bootfiles with new ones.
283    (But they are stored in the same place.)
284    
285    ----------------------------------------------------------------------
286    Name: Matthias Blume
287    Date: 2002/03/24 22:40:00 EST
288    Tag: blume-20020324-bootfiles
289    Description:
290    
291    Made the bootfiles that Allen asked for.
292    
293    ----------------------------------------------------------------------
294    Name: Allen Leung
295    Date: 2002/03/23 15:50:00 EST
296    Tag: leunga-20020323-flint-cps-rcc-primops
297    Description:
298    
299      1. Changes to FLINT primops:
300    
301        (* make a call to a C-function;
302         * The primop carries C function prototype information and specifies
303         * which of its (ML-) arguments are floating point. C prototype
304         * information is for use by the backend, ML information is for
305         * use by the CPS converter. *)
306      | RAW_CCALL of { c_proto: CTypes.c_proto,
307                       ml_args: ccall_type list,
308                       ml_res_opt: ccall_type option,
309                       reentrant : bool
310                     } option
311       (* Allocate uninitialized storage on the heap.
312        * The record is meant to hold short-lived C objects, i.e., they
313        * are not ML pointers.  With the tag, the representation is
314        * the same as RECORD with tag tag_raw32 (sz=4), or tag_fblock (sz=8)
315        *)
316      | RAW_RECORD of {tag:bool,sz:int}
317      and ccall_type = CCALL_INT32 | CCALL_REAL64 | CCALL_ML_PTR
318    
319      2.  These CPS primops are now overloaded:
320    
321           rawload of {kind:numkind}
322           rawstore of {kind:numkind}
323    
324          The one argument form is:
325    
326             rawload {kind} address
327    
328          The two argument form is:
329    
330             rawload {kind} [ml object, byte-offset]
331    
332      3. RAW_CCALL/RCC now takes two extra arguments:
333    
334         a. The first is whether the C call is reentrant, i.e., whether
335            ML state should be saved and restored.
336         b. The second argument is a string argument specifying the name of
337            library and the C function.
338    
339         These things are currently not handled in the code generator, yet.
340    
341      4. In CProto,
342    
343         An encoding type of "bool" means "ml object" and is mapped into
344         C prototype of PTR.  Note that "bool" is different than "string",
345         even though "string" is also mapped into PTR, because "bool"
346         is assigned an CPS type of BOGt, while "string" is assigned INT32t.
347    
348      5. Pickler/unpicker
349    
350         Changed to handle RAW_RECORD and newest RAW_CCALL
351    
352      6. MLRiscGen,
353    
354         1. Changed to handle the new rawload/rawstore/rawrecord operators.
355         2. Code for handling C Calls has been moved to a new module CPSCCalls,
356            in the file CodeGen/cpscompile/cps-c-calls.sml
357    
358      7. Added the conditional move operator
359    
360             condmove of branch
361    
362         to cps.  Generation of this is still buggy so it is currently
363         disabled.
364    
365    ----------------------------------------------------------------------
366  Name: Lal George  Name: Lal George
367  Date: 2002/03/22 14:18:25 EST  Date: 2002/03/22 14:18:25 EST
368  Tag: george-20020322-cps-branch-prob  Tag: george-20020322-cps-branch-prob

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