The column head i/p contains the integer and pointer size used in units of
bytes.
The subdirectories with the same name in mach contain the sources.
-A * in the column headed 'fp' indicates whether floating point can be used
-for that particular machine.
+A * in the column headed 'fp' indicates that floating point can be used
+for that particular machine. A + in that column indicates that floating
+point is only available under the '-fp' option. In this case, software
+floating point emulation is used.
.TS
c c c c c c c
l l l l l l l.
Basic
Occam
-m68k2 M68000/Unisoft 2/4 C m68k2
+m68k2 M68000/Unisoft 2/4 C + m68k2
Pascal
Basic
Occam
-m68k4 M68000/Unisoft 4/4 C m68k4
+m68k4 M68000/Unisoft 4/4 C + m68k4
Pascal m68k2
Basic
Occam
-pmds M68000/PMDS 2/4 C pmds Philips Micro
+pmds M68000/PMDS 2/4 C + pmds Philips Micro
Pascal m68k2 Devel. System
Basic
Occam
-pmds4 M68000/PMDS 4/4 C pmds4 Philips Micro
+pmds4 M68000/PMDS 4/4 C + pmds4 Philips Micro
Pascal m68k2 Devel. System
Basic m68k4
Occam
-mantra M68000/SysV.0 4/4 C mantra
+mantra M68000/SysV.0 4/4 C + mantra
Pascal m68k2
Basic m68k4
Occam
-m68020 M68020/V/68 4/4 C m68020
+m68020 M68020/V/68 4/4 C + m68020
R2V2.1 Pascal
Basic
Occam
-sun3 SUN 3 R3.0 4/4 C sun3
+sun3 SUN 3 R3.0 4/4 C + sun3
Pascal m68020
Basic
Occam
-sun2 SUN 2 R3.0 4/4 C sun2
+sun2 SUN 2 R3.0 4/4 C + sun2
Pascal m68k4
Basic m68k2
Occam
-i86 IBM PC/IX 2/2 C i86 IBM PC with PC/IX
+i86 IBM PC/IX 2/2 C + i86 IBM PC with PC/IX
Pascal Causes kernel crashes
Basic
Occam
+xenix3 Microsoft Xenix V3 2/2 C + xenix3 IBM AT with Xenix
+ Pascal i86
+ Basic
+ Occam
+
z8000 Zilog 8000 2/2 C z8000 Central Data
Pascal CPU board
Basic Uses assembler/loader
Occam
-int Same as int22
int22 EM machine 2/2 C * int22 Needs interpreter
Pascal
Basic
The first one can only interpret 2/2 e.out files,
the other takes 2/4 and 4/4 files.
The PDP 11 interpreter executes floating point instructions.
-The interpreter on the PMDS traps if you try to use floating point.
+The interpreter for the M68000 traps if you try to use floating point.
.LP
The program \fBem\fP in the bin directory calls the appropriate
interpreter.
and contains one character: \f50C\fP.
.PP
When the text of a comment starts with a '\f5$\fP', it may be a pragma.
-Currently, two pragmas exist:
+Currently, the following pragmas exist:
.DS
.ft 5
-(*$F (F stands for Foreign) *)
-(*$R[+|-] (Runtime checks, on or off) *)
+(*$F (F stands for Foreign) *)
+(*$R[+|-] (Runtime checks, on or off, default on) *)
+(*$A[+|-] (Array bound checks, on or off, default off) *)
+(*$U (Allow for underscores within identifiers) *)
.ft P
.DE
The Foreign pragma is only meaningful in a \f5DEFINITION MODULE\fP,
checks when assigning a \f5CARDINAL\fP to an \f5INTEGER\fP and vice versa,
and checks that \f5FOR\fP-loop control-variables are not changed
in the body of the loop.
+Array bound checks can be enabled, because many EM implementations do not
+implement the array bound checking of the EM array instructions.
+When enabled, the compiler generates a check before generating an
+EM array instruction.
+Even when underscores are enabled, they still may not start an identifier.
.PP
Constants of type \f5LONGINT\fP are integers with a suffix letter \f5D\fP
(for instance \f51987D\fP).
.IP "cardinal overflow"
.br
This error is detected, unless runtime checks are disabled.
-This message is also given on cardinal underflow.
+.IP "cardinal underflow"
+.br
+This error is detected, unless runtime checks are disabled.
.IP "real overflow"
.br
The detection of this error depends on the EM implementation.
.PP
See [4,5,6] for a detailed explanation.
.NH 1
+The procedure call interface
+.PP
+Parameters are pushed on the stack in reversed order, so that the EM AB
+(argument base) register indicates the first parameter.
+For VAR parameters, its address is passed, for value parameters its value.
+The only exception to this rule is with conformant arrays.
+For conformant arrays, the address is passed, and an array descriptor is
+passed. The descriptor is an EM array descriptor. It consists of three
+fields: the lower bound (always 0), upper bound - lower bound, and the
+size of the elements.
+The descriptor is pushed first.
+If the parameter is a value parameter, the called routine must make sure
+that its value is never changed, for instance by making its own copy
+of the array.
+.NH 1
References
.IP [1]
Niklaus Wirth,
public / ack.git / commitdiff