Accelerator Manual (G06.24+, H06.03+)

Preparing Your Program for TNS/R Systems

Accelerator Manual—527303-002

2-9

Segment Wrapping

Examples

The following examples show addressing operations that might not wrap back on the

segment on TNS/R systems as they do on TNS systems.

STRUCT s(*);

BEGIN

INT i;

INT(32) d;

INT j;

END;

PROC exam;

BEGIN

INT .p (s);

STRUCT s2(s);

@p := -1; ! -1 = 65535 (unsigned), structure starts at

! the last word of the user data segment and

! goes past the end

s2 ':=' p FOR $LEN(s2) BYTES; ! On TNS/R systems,

p.d := %h12345678%d; ! these operations

p.j := 6; ! might wrap or trap

ENF;

The structure defined by P starts near the end of the user data segment and goes past

the end. On TNS systems, this addressing operation wraps back to G[0], as shown by

the dotted line in the following figure. On TNS/R systems, this addressing operation

might wrap or trap.

G [0]

G [65535]

SG [0]

User Data Segment

(Relative Segment 0)

System Data Segment

(Relative Segment 1)

VST0202.vdd