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revision 1171, Fri Mar 22 20:41:43 2002 UTC revision 1181, Wed Mar 27 21:27:27 2002 UTC
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13  Description:  Description:
14    
15  ----------------------------------------------------------------------  ----------------------------------------------------------------------
16    Name: Matthias Blume
17    Date: 2002/03/27 16:27:00 EST
18    Tag: blume-20020327-mlrisc-divisions
19    Description:
20    
21    Added support for all four division operations (ML's div, mod, quot,
22    and rem) to MLRISC.  In the course of doing so, I also rationalized
23    the naming (no more annoying switch-around of DIV and QUOT), by
24    parameterizing the operation by div_rounding_mode (which can be either
25    DIV_TO_ZERO or DIV_TO_NEGINF).
26    
27    The generic MLTreeGen functor takes care of compiling all four
28    operations down to only round-to-zero div.
29    
30    Missing pieces:
31    
32      * Doing something smarter than relying on MLTreeGen on architectures
33        like, e.g., the x86 where hardware division delivers both quotient and
34        remainder at the same time.  With this, the implementation of the
35        round-to-neginf operations could be further streamlined.
36    
37      * Remove inlining support for div/mod/rem from the frontend and replace it
38        with primops that get carried through to the backend.  Do this for all
39        int and word types.
40    
41    ----------------------------------------------------------------------
42    Name: Matthias Blume
43    Date: 2002/03/25 17:25:00 EST
44    Tag: blume-20020325-divmod
45    Description:
46    
47    I improved (hopefully without breaking them) the implementation of Int.div,
48    Int.mod, and Int.rem.   For this, the code in translate.sml now takes
49    advantage of the following observations:
50    
51      Let  q = x quot y      r = x rem y
52           d = x div  y      m = x mod y
53    
54    where "quot" is the round-to-zero version of integer division that
55    hardware usually provides.  Then we have:
56    
57         r = x - q * y        where neither the * nor the - will overflow
58         d = if q >= 0 orelse x = q * y then q else q - 1
59                              where neither the * nor the - will overflow
60         m = if q >= 0 orelse r = 0 then r else r + y
61                              where the + will not overflow
62    
63    This results in substantial simplification of the generated code.
64    The following table shows the number of CFG nodes and edges generated
65    for
66            fun f (x, y) = x OPER y
67            (* with OPER \in div, mod, quot, rem *)
68    
69    
70        OPER | nodes(old) | edges(old) | nodes(new) | edges(new)
71        --------------------------------------------------------
72         div |         24 |         39 |         12 |         16
73         mod |         41 |         71 |         12 |         16
74        quot |          8 |         10 |          8 |         10
75         rem |         10 |         14 |          8 |         10
76    
77    
78    ----------------------------------------------------------------------
79    Name: Matthias Blume
80    Date: 2002/03/25 22:06:00 EST
81    Tag: blume-20020325-cprotobug
82    Description:
83    
84    Fixed a bug in cproto (c prototype decoder).
85    
86    ----------------------------------------------------------------------
87    Name: Matthias Blume
88    Date: 2002/03/25 16:00:00 EST
89    Tag: blume-20020325-raw-primops
90    Description:
91    
92    I did some cleanup to Allen's new primop code and
93    replaced yesterday's bootfiles with new ones.
94    (But they are stored in the same place.)
95    
96    ----------------------------------------------------------------------
97    Name: Matthias Blume
98    Date: 2002/03/24 22:40:00 EST
99    Tag: blume-20020324-bootfiles
100    Description:
101    
102    Made the bootfiles that Allen asked for.
103    
104    ----------------------------------------------------------------------
105    Name: Allen Leung
106    Date: 2002/03/23 15:50:00 EST
107    Tag: leunga-20020323-flint-cps-rcc-primops
108    Description:
109    
110      1. Changes to FLINT primops:
111    
112        (* make a call to a C-function;
113         * The primop carries C function prototype information and specifies
114         * which of its (ML-) arguments are floating point. C prototype
115         * information is for use by the backend, ML information is for
116         * use by the CPS converter. *)
117      | RAW_CCALL of { c_proto: CTypes.c_proto,
118                       ml_args: ccall_type list,
119                       ml_res_opt: ccall_type option,
120                       reentrant : bool
121                     } option
122       (* Allocate uninitialized storage on the heap.
123        * The record is meant to hold short-lived C objects, i.e., they
124        * are not ML pointers.  With the tag, the representation is
125        * the same as RECORD with tag tag_raw32 (sz=4), or tag_fblock (sz=8)
126        *)
127      | RAW_RECORD of {tag:bool,sz:int}
128      and ccall_type = CCALL_INT32 | CCALL_REAL64 | CCALL_ML_PTR
129    
130      2.  These CPS primops are now overloaded:
131    
132           rawload of {kind:numkind}
133           rawstore of {kind:numkind}
134    
135          The one argument form is:
136    
137             rawload {kind} address
138    
139          The two argument form is:
140    
141             rawload {kind} [ml object, byte-offset]
142    
143      3. RAW_CCALL/RCC now takes two extra arguments:
144    
145         a. The first is whether the C call is reentrant, i.e., whether
146            ML state should be saved and restored.
147         b. The second argument is a string argument specifying the name of
148            library and the C function.
149    
150         These things are currently not handled in the code generator, yet.
151    
152      4. In CProto,
153    
154         An encoding type of "bool" means "ml object" and is mapped into
155         C prototype of PTR.  Note that "bool" is different than "string",
156         even though "string" is also mapped into PTR, because "bool"
157         is assigned an CPS type of BOGt, while "string" is assigned INT32t.
158    
159      5. Pickler/unpicker
160    
161         Changed to handle RAW_RECORD and newest RAW_CCALL
162    
163      6. MLRiscGen,
164    
165         1. Changed to handle the new rawload/rawstore/rawrecord operators.
166         2. Code for handling C Calls has been moved to a new module CPSCCalls,
167            in the file CodeGen/cpscompile/cps-c-calls.sml
168    
169      7. Added the conditional move operator
170    
171             condmove of branch
172    
173         to cps.  Generation of this is still buggy so it is currently
174         disabled.
175    
176    ----------------------------------------------------------------------
177  Name: Lal George  Name: Lal George
178  Date: 2002/03/22 14:18:25 EST  Date: 2002/03/22 14:18:25 EST
179  Tag: george-20020322-cps-branch-prob  Tag: george-20020322-cps-branch-prob

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