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Length: 1455 (0x5af)
Types: TextFile
Notes: UNIX file
Names: »epdtoadr.3«
└─⟦26887b7e0⟧ Bits:30009717 Comet 32 harddisk image
└─⟦28c352965⟧ »/a« UNIX Filesystem
└─⟦this⟧ »usr/man/man3/epdtoadr.3«
.ig @(#)epdtoadr.3 2.1 7/1/84 @(#)Copyright (C) 1983 by National Semiconductor Corp. .. .TH EPDTOADR 3 .SH NAME epdtoadr \- convert external procedure descriptor to absolute address .SH SYNOPSIS .nf .B epdtoadr(descriptor) .B long descriptor; .fi .SH DESCRIPTION .I Epdtoadr converts an external procedure descriptor to an absolute address. An external procedure descriptor is a 32-bit value used by the CXP and CXPD instructions to call a procedure. Such descriptors are used by C for procedure variables. .PP An external procedure descriptor consists of a mod value and an offset value. The mod value is contained in the low 16 bits of the descriptor, and the offset is contained in the high 16 bits. The mod value is the address of the module table entry for the called procedure. The offset value is an index into the module's program base. The program base is a 32-bit number located eight bytes into the module table entry. The CXP and CXPD instructions calculate the absolute address of the procedure to call by adding the offset value to the program base value. The .I epdtoadr function duplicates these calculations. .PP .I Epdtoadr is useful when the address of a procedure is wanted for typeout or to provide the data for BSR or JUMP instructions. .PP .SH BUGS This is a nonstandard function. Most other UNIX systems do not require any conversion, since the value used to call a procedure is the same as the address of the procedure.