U UNIVAC 1218 - Bitsavers

16. FLOATING POINT ARITHMETIC
GENERAL DESCRIPTION: This subroutine performs add, subtract, multiply, and
divide operations on floating point numbers. This is the same subroutine as
FLOAT except for I/O parameters and the addition of FSUB.
CALLING SEQUENCE:
Address Mnemonic Operand
L IRJP (FADD, FSUB, FMUL, OR FDIV)
L+l 0 TAG 1
L+2 0 TAG 2
L+3 0 TAG 3
L+4 (Return)
TAG 1 and TAG 2 are the addresses of the least significant halves of operands 1
and 2. TAG 3 is the address of the least significant half of the answer.
For FADD and FMUL, the order of operands 1 and 2 is not important. For FSUB,
operand 1 is the minuend and operand 2 the subtrahend. For FDIV, operand 1
is the dividend and operand 2 the divisor. Register A also contains the
answer upon return from the routine.
RESTRICTIONS: The routine must be wholly contained with one bank. TAG I,
TAG 2, and TAG 3 must be in the same bank as the return jump
instruction.
V-A-16