SENTRY - enter B function, with stack advance.

Usage:

sentry (symdefs)[,endptr][,(options)]

Examples:

sentry (printf,.prntf),,ARB
sentry (getcha,get.ch),end,INHIB
sentry .write

Where:

symdefs

is a list of entry point names for the GMAP function. They must be valid GMAP symbols. If only one name is given, it need not be enclosed in parentheses.

endptr

should be a pointer to the end of the function. If it is omitted, it will be set to the label "end" which must be defined using the BEND macro.

options

is a list of keywords used to indicate different options in the entry sequence. If more than one option is desired, the list should be enclosed in parentheses. Currently three options are defined:

• ARB specifies that this routine accepts a pointer to an arbitrary number of arguments, instead of the arguments themselves.
• INHIB specifies that break handling be inhibited during the execution of this routine (use the exact word - "INHIB").
• STORE specifies that the routine expects its first two arguments in storage on the stack rather than in the A and Q registers.

Description:

This is a standard method of starting a B function. When the GMAP subroutine is entered, the stack will be advanced and the first two arguments will still be in the A and Q registers. Space for arguments should be reserved using the ARGDEF macro. If an arbitrary number of arguments are expected, the ARB option should be used, in which case the entry to the program will receive a pointer to the list of arguments in the A register.

The use of the INHIB option will cause the run-time library to hold any breaks in abeyance until this routine completes execution.

Approximate equivalent code generated:

*      sentry  myfunc
       symdef  myfunc
myfunc tra     *+1
       tsx0    .entry
       zero    .frame,end
       symref  .retrn,.entry
*      sentry  printf,,arb
       symdef  printf
printf tra     *+1
       tsx0    .vntry
       zero    .frame,end
       symref  .retrn,.vntry

See Also:

expl b bmac argdef

for defining arguments.

expl b bmac auto

for defining local storage.

expl b bmac bretrn

for function return.

expl b bmac advnce

advance stack only.

expl b bmac bentry

simplified function entry.

Copyright © 1996, Thinkage Ltd.