## 2 CVT$

3 CVT$CONVERT_FLOAT The Convert Floating-Point Data Type routine provides a simplified options-interface for converting a floating-point data type to another supported floating-point data type. Format CVT$CONVERT_FLOAT input_value, input_type_code, output_value, output_type_code, options 4 Returns OpenVMS usage:cond_value type: longword (unsigned) access: write only mechanism: by value 4 Arguments input_value OpenVMS usage:varying_arg type: unspecified access: read only mechanism: by reference The address of a data area containing a floating-point number that is to be converted. The input_value argument may contain floating-point data in F_Floating, D_Floating, G_Floating, H_ Floating, IEEE_S_Floating, IEEE_T_Floating, IEEE_X_Floating, IBM_ Long_Floating, IBM_Short_Floating, or CRAY_Floating format. The value of the input_type_code argument determines the format and size of the input_value argument. input_type_code OpenVMS usage:longword_unsigned type: longword (unsigned) access: read only mechanism: by value The value of a longword bit mask specifying the type of floating- point data being passed in the input_value argument. Valid type codes are: Size in input_type_code Format Bytes CVT$K_VAX_F F_Floating 4 CVT$K_VAX_D D_Floating 8 CVT$K_VAX_G G_Floating 8 CVT$K_VAX_H H_Floating 16 CVT$K_IEEE_S IEEE_S_Floating 4 CVT$K_IEEE_T IEEE_T_Floating 8 CVT$K_IEEE_X IEEE_X_Floating 16 CVT$K_IBM_LONG IBM_Long_Floating 8 CVT$K_IBM_SHORT IBM_Short_Floating 4 CVT$K_CRAY CRAY_Floating 8 Declarations for the input_type_code argument are in the $CVTDEF module found in the system symbol libraries. output_value OpenVMS usage:varying_arg type: unspecified access: write only mechanism: by reference The address of a data area that receives the converted floating- point number. The output_value argument can contain floating- point data in F_Floating, D_Floating, G_Floating, H_Floating, IEEE_S_Floating, IEEE_T_Floating, IEEE_X_Floating, IBM_Long_ Floating, IBM_Short_Floating, or CRAY_Floating format. The value of the output_type_code argument determines the size and format of the data placed into the output_value argument. output_type_code OpenVMS usage:longword_unsigned type: longword (unsigned) access: read only mechanism: by value The value of a longword bit mask specifying the type of floating- point data that the input_value argument will be converted into and returned in the output_value argument. Valid type codes are: Size in output_type_code Format Bytes CVT$K_VAX_F F_Floating 4 CVT$K_VAX_D D_Floating 8 CVT$K_VAX_G G_Floating 8 CVT$K_VAX_H H_Floating 16 CVT$K_IEEE_S IEEE_S_Floating 4 CVT$K_IEEE_T IEEE_T_Floating 8 CVT$K_IEEE_X IEEE_X_Floating 16 CVT$K_IBM_LONG IBM_Long_Floating 8 CVT$K_IBM_SHORT IBM_Short_Floating 4 CVT$K_CRAY CRAY_Floating 8 Declarations for the output_type_code argument are in the $CVTDEF module found in the system symbol libraries. options OpenVMS usage:mask_longword type: longword (unsigned) access: read only mechanism: by value Conversion option specifier. The options argument is the address of a longword bit mask in which each option bit set causes the corresponding option to be used during the conversion. The following options can be specified using the options argument: Option Description CVT$M_ROUND_TO_ The default rounding option for NEAREST conversions to IEEE data types. This IEEE Std. 754 rounding mode results in the representable output value nearest to the infinitely precise result. If the two nearest representable values are equally near, the one whose least significant bit is 0 is the result. CVT$M_VAX_ROUNDING The default rounding option for conversions to non-IEEE data types. Performs "traditional" style rounding. This mode results in the representable output value nearest to the infinitely precise result. If the two nearest representable values are equally near, the output value is the closest to either positive infinity or negative infinity, depending on the sign of the input value. CVT$M_TRUNCATE Round the output value toward zero (truncate). CVT$M_ROUND_TO_POS Round the output value toward positive infinity. CVT$M_ROUND_TO_NEG Round the output value toward negative infinity. CVT$M_BIG_ENDIAN Interprets IEEE data types as Big Endian. CVT$M_ERR_UNDERFLOW Report underflow conditions as errors. Declarations for the options argument are in the $CVTDEF module found in the system symbol libraries. 3 CVT$FTOF The Convert Floating-Point Data Type routine converts floating- point data types to other supported floating-point data types and allows additional control over the converted results. CVT$FTOF functionality is also available on other Digital-supported platforms. Format status = CVT$FTOF input_value, input_type_code, output_value, output_type_code, options 4 Returns OpenVMS usage:mask_longword type: longword (unsigned) access: write only mechanism: by value The status return value is an unsigned longword bit mask containing the condition codes raised by the function. CVT$FTOF returns CVT$K_NORMAL; otherwise, it sets one or more recoverable and unrecoverable conditions. Return status values are in the $CVTDEF module in the system symbol libraries. 4 Arguments input_value OpenVMS usage:varying_arg type: unspecified access: read only mechanism: by reference The address of a data area containing a floating-point number to be converted. The number can be floating-point data in one of the following formats: F_Floating Big_Endian_IEEE_S_Floating D_Floating Big_Endian_IEEE_T_Floating G_Floating Big_Endian_IEEE_X_Floating H_Floating IBM_Long_Floating IEEE_S_Floating IBM_Short_Floating IEEE_T_Floating CRAY_Floating_Single IEEE_X_Floating The value of the input_type_code argument determines the format and size of the input_value argument. input_type_code OpenVMS usage:longword_unsigned type: longword (unsigned) access: read only mechanism: by value The value of a longword bit mask specifying the type of floating- point data being passed in the input_value argument. Valid type codes are: Size in Input_type_code Format Bytes CVT$K_VAX_F F_Floating 4 CVT$K_VAX_D D_Floating 8 CVT$K_VAX_G G_Floating 8 CVT$K_VAX_H H_Floating 16 CVT$K_IEEE_S IEEE_S_Floating 4 CVT$K_IEEE_T IEEE_T_Floating 8 CVT$K_IEEE_X IEEE_X_Floating 16 CVT$K_BIG_ENDIAN_IEEE_S Big_Endian_IEEE_S_Floating 4 CVT$K_BIG_ENDIAN_IEEE_T Big_Endian_IEEE_T_Floating 8 CVT$K_BIG_ENDIAN_IEEE_X Big_Endian_IEEE_X_Floating 16 CVT$K_IBM_LONG IBM_Long_Floating 8 CVT$K_IBM_SHORT IBM_Short_Floating 4 CVT$K_CRAY_SINGLE CRAY_Floating 8 Declarations for the input_type_code argument are in the $CVTDEF module found in the system symbol libraries. output_value OpenVMS usage:varying_arg type: unspecified access: write only mechanism: by reference The address of a data area that receives the converted floating- point number. The number can be floating-point data in F_ Floating, D_Floating, G_Floating, H_Floating, IEEE_S_Floating, IEEE_T_Floating, IEEE_X_Floating, Big_Endian_IEEE_S_Floating, Big_Endian_IEEE_T_Floating, Big_Endian_IEEE_X_Floating, IBM_Long_ Floating, IBM_Short_Floating, or CRAY_Floating_Single format. The value of the output_type_code argument determines the size and format of the converted floating-point number. output_type_code OpenVMS usage:longword_unsigned type: longword (unsigned) access: read only mechanism: by value The value of a longword bit mask specifying the type of floating- point data that the input_value argument will be converted into and returned in the output_value argument. Valid type codes are: Size in Output_type_code Format Bytes CVT$K_VAX_F F_Floating 4 CVT$K_VAX_D D_Floating 8 CVT$K_VAX_G G_Floating 8 CVT$K_VAX_H H_Floating 16 CVT$K_IEEE_S IEEE_S_Floating 4 CVT$K_IEEE_T IEEE_T_Floating 8 CVT$K_IEEE_X IEEE_X_Floating 16 CVT$K_BIG_ENDIAN_IEEE_S Big_Endian_IEEE_S_Floating 4 CVT$K_BIG_ENDIAN_IEEE_T Big_Endian_IEEE_T_Floating 8 CVT$K_BIG_ENDIAN_IEEE_X Big_Endian_IEEE_X_Floating 16 CVT$K_IBM_LONG IBM_Long_Floating 8 CVT$K_IBM_SHORT IBM_Short_Floating 4 CVT$K_CRAY_SINGLE CRAY_Floating 8 Declarations for the output_type_code argument are in the $CVTDEF module found in the system symbol libraries. options OpenVMS usage:mask_longword type: longword (unsigned) access: read only mechanism: by value Conversion option specifier. The options argument is the address of a longword bit mask in which each option bit set causes the corresponding option to be used during the conversion. Provide a zero (0) value to the options argument to select default behavior or choose one or more options (status condition option, rounding options, "FORCE" options, CRAY and IBM options) from the following tables. Specify only the options that apply to your conversion. A conflicting or incompatible options argument is reported as an error (CVT$M_INVALID_OPTION). Applicable Conversion Option Description Status Condition Option All CVT$M_REPORT_ALL Report all applicable status conditions as the default. The reporting of recoverable status conditions is disabled by default when this option is not used. Rounding Options All CVT$M_ROUND_TO_ The default rounding option NEAREST for conversions to IEEE data types. This IEEE Std. 754 rounding mode results in the representable output value nearest to the infinitely precise result. If the two nearest representable values are equally near, the one whose least significant bit is 0 is the result. All CVT$M_BIASED_ The default rounding option for ROUNDING conversions to non-IEEE data types. Performs "traditional" style rounding. This mode results in the representable output value nearest to the infinitely precise result. If the two nearest representable values are equally near, the output value is the closest to either positive infinity or negative infinity depending on the sign of the input value. All CVT$M_ROUND_TO_ Round the output value toward ZERO zero (truncate). All CVT$M_ROUND_TO_POS Round the output value toward positive infinity. All CVT$M_ROUND_TO_NEG Round the output value toward negative infinity. "FORCE" Options All CVT$M_FORCE_ALL_ Apply all applicable "FORCE" SPECIAL_VALUES options for the current conversion. IEEE CVT$M_FORCE_ Force a denormalized IEEE DENORM_TO_ZERO output value to zero. IEEE CVT$M_FORCE_INF_ Force a positive IEEE infinite TO_MAX_FLOAT output value to +max_float and force a negative IEEE infinite output value to -max_float. IEEE or VAX CVT$M_FORCE_ Force an invalid IEEE NaN (not INVALID_TO_ZERO a number) output value or a VAX ROP (reserved operand) output value to zero. CRAY Format Conversion Options CRAY CVT$M_ALLOW_ Allow an input/output exponent OVRFLW_RANGE_ value > 60000 (8). VALUES CRAY CVT$M_ALLOW_ Allow an input/output exponent UDRFLW_RANGE_ value < 20000 (8). VALUES IBM Format Conversion Option IBM CVT$M_ALLOW_ Allow unnormalized input UNNORMALIZED_ arguments. Allow an VALUES unnormalized output value for a small value that would normalize to zero. The maximum representable floating-point values (max_float) for the IEEE_S_Floating, IEEE_T_Floating, IEEE_X_Floating, Big_ Endian_IEEE_S_Floating, Big_Endian_IEEE_T_Floating, and Big_ Endian_IEEE_X_Floating formats are: Data Type Value for: max_float S Decimal: 3.402823e38 T Decimal: 1.797693134862316e308 X Decimal: 1.189731495357231765085759326628007016196477e4932 Declarations for the options argument are in the $CVTDEF module found in the system symbol libraries.