Am 08.11.2017 um 18:47 schrieb Thomas David Rivers:
Frank Swarbrick wrote:
Doesn't that make for fairly large executables?
Well - it can - but a trimmed down C library is surprisingly small.
Of course - if you're dragging C++ into this, then things get bigger; but
again - that's not the library usually, it's the templates, etc.. that
your
program instantiates...
It seems, in practice, to not be an issue at all.
- Dave Rivers -
Just to give an example, how small a runtime library can be:
my New Stanford Pascal compiler has a runtime library, which is also
linked with every
Pascal program (in the same way as Dave describes). The Pascal compiler
itself is
a Pascal program (ca. 15.000 lines at the moment - pass one, generating
P-Code; the
P-Code is later translated to 370 machine code, which is done in pass
two, which has
another 12000 lines). For the following discussion, PASCAL1 (pass one)
only serves as
an example of a (large) Pascal program.
Pass one has, after compilation, the following size:
ENTRY ADDRESS 1E940
TOTAL LENGTH 30AC8
****PASCAL1 NOW REPLACED IN DATA SET
AUTHORIZATION CODE IS 0.
the size of PASCAL1 is 200 k, ca.
Excerpts from the Linker listing:
CONTROL SECTION ENTRY
NAME ORIGIN LENGTH NAME LOCATION NAME LOCATION
$PASMAI# 00 E28
$PRV0001 E28 AC
$PRV0002 ED8 C8
$PRV0003 FA0 E8
$PRV0004 1088 78
The runtime starts here:
$PASENT 1E940 53E0
$PASINT 1EE88 $PASTRC 1F0CC
IHNERRM 1FB36 ERRMON 1FB36
IHCERRE 1FB6A $PASSYS 1FB78
$PASCSP2 2005A
$PASLIB# 23D20 2C
$LIBX002 23D50 BC
$LIBX004 23E10 118
that is:
the "core" runtime, written in ASSEMBLER, is $PASENT,
and its size is 21 k (!).
The "library" functions from $PASLIB (written in Pascal)
are added for convenience, although only very few of them
are really used in the compiler.
All those "library" function are located in the area from 23D20 to
30AC8 and need 52 k ca.
BTW: I just discovered that I added an unneeded member called PASUTILS,
which could be eliminated, so 8 k could by saved :-)
$PASUTI# 2E938 4A
$UTIL003 2E988 C0
HALT 2EA48 A4
DATETIME 2EAF0 184
DATTIM10 2EC78 1C4
TERMIN 2EE40 290
TERMOUT 2F0D0 290
ASSIGN 2F360 320
ASSIGNME 2F680 1A4
CLRSCRN 2F828 1B8
MOVEPARM 2F9E0 178
TOUPPER 2FB58 104
TOUPPERS 2FC60 10C
$UTIL016 2FD70 118
$UTIL017 2FE88 33C
DUMPSTOR 301C8 138
INTTOSTR 30300 284
IVALSTR 30588 3F8
READSYMB 30980 144
if you are interested in the compiler, look here:
http://bernd-oppolzer.de/job9.htm
or here:
https://www.facebook.com/StanfordPascal/?ref=aymt_homepage_panel
the compiler runs on old CMS and MVS versions, but on modern z/OS, too
(limited to AMODE 24,
at the moment), and probably on z/VM (not tested yet). You can download
the compiler
using the links above.
Kind regards
Bernd
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