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

    Purpose:        Compare two packed decimal strings and set the
                    condition codes
    Format:         opcode len.rw,scr1addr.ab,src2addr.ab       ;3 operand
                    opcode src1len.rw,src1addr.ab,
                           src2len.rw,src2addr.ab               ;4 operand
    Operation:      ({src1addr + ZEXT(len/2)}:src1addr) =
                    ({src2addr + ZEXT(len/2)}:src2addr)         ;3 operand
                    ({src1addr + ZEXT(src1len/2)}:src1addr =
                    ({arc2addr + ZEXT(src2len/2)}:src2addr      ;4 operand
    C. Codes:       N = {{src1 string} LSS {src2 string}}, V = 0,
                    Z = {{src1 string} EQL {src2 string}}, C = 0
    Exceptions:     Reserved operand
    Opcodes:        35    CMPP3    Compare packed 3 operand
                    37    CMPP4    Compare packed 4 operand
    Description:    In 3-operand format, the source 1 string specified
                    by src1addr and len is compared with the source 2
                    string specified by the src2addr and len. In
                    4-operand format, the source 1 string is specified
                    by src1addr and src1len, the source 2 string by
                    src2addr and src2len. The only action in either
                    case is to affect the condition codes.
    Notes:          After execution of CMPP3 or CMPP4:

                    R0 = 0
                    R1 = address of the byte containing the
                         most-significant digit of string 1
                    R2 = 0
                    R3 = address of the byte containing the
                         most-significant digit of string 2