/sys$common/syshlp/helplib.hlb MACRO, VAX MACRO Assembler, Instructions, SUBxx  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Purpose:        Perform arithmetic subtraction
    Format:         opcode sub.rx,dif.mx                    ;2 operand
                    opcode sub.rx,min.rx,dif.wx             ;3 operand
    Operation:      dif = dif - sub                         ;2 operand
                    dif = min - sub                         ;3 operand
    C. Codes:       N = {dif LSS 0}, Z = {dif EQL 0},
                    V = {overflow}, C = 0 (floating),
                    C = {borrow from MSB (integer)}
    Exceptions:     Integer/floating overflow, floating
                    underflow, reserved operand
    Opcodes:        82    SUBB2    Subtract byte 2 operand
                    83    SUBB3    Subtract byte 3 operand
                    A2    SUBW2    Subtract word 2 operand
                    A3    SUBW3    Subtract word 3 operand
                    C2    SUBL2    Subtract long 2 operand
                    C3    SUBL3    Subtract long 3 operand
                    42    SUBF2    Subtract F_floating 2 operand
                    43    SUBF3    Subtract F_floating 3 operand
                    62    SUBD2    Subtract D_floating 2 operand
                    63    SUBD3    Subtract D_floating 3 operand
                    42FD  SUBG2    Subtract G_floating 2 operand
                    43FD  SUBG3    Subtract G_floating 3 operand
                    62FD  SUBH2    Subtract H_floating 2 operand

                           63FD  SUBH3    Subtract H_floating 3 operand