/* Decimal floating point support for GDB. Copyright (C) 2007-2017 Free Software Foundation, Inc. This file is part of GDB. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . */ #include "defs.h" #include "expression.h" #include "dfp.h" /* The order of the following headers is important for making sure decNumber structure is large enough to hold decimal128 digits. */ #include "dpd/decimal128.h" #include "dpd/decimal64.h" #include "dpd/decimal32.h" /* When using decimal128, this is the maximum string length + 1 (value comes from libdecnumber's DECIMAL128_String constant). */ #define MAX_DECIMAL_STRING 43 /* In GDB, we are using an array of gdb_byte to represent decimal values. They are stored in host byte order. This routine does the conversion if the target byte order is different. */ static void match_endianness (const gdb_byte *from, int len, enum bfd_endian byte_order, gdb_byte *to) { int i; #if WORDS_BIGENDIAN #define OPPOSITE_BYTE_ORDER BFD_ENDIAN_LITTLE #else #define OPPOSITE_BYTE_ORDER BFD_ENDIAN_BIG #endif if (byte_order == OPPOSITE_BYTE_ORDER) for (i = 0; i < len; i++) to[i] = from[len - i - 1]; else for (i = 0; i < len; i++) to[i] = from[i]; return; } /* Helper function to get the appropriate libdecnumber context for each size of decimal float. */ static void set_decnumber_context (decContext *ctx, int len) { switch (len) { case 4: decContextDefault (ctx, DEC_INIT_DECIMAL32); break; case 8: decContextDefault (ctx, DEC_INIT_DECIMAL64); break; case 16: decContextDefault (ctx, DEC_INIT_DECIMAL128); break; } ctx->traps = 0; } /* Check for errors signaled in the decimal context structure. */ static void decimal_check_errors (decContext *ctx) { /* An error here could be a division by zero, an overflow, an underflow or an invalid operation (from the DEC_Errors constant in decContext.h). Since GDB doesn't complain about division by zero, overflow or underflow errors for binary floating, we won't complain about them for decimal floating either. */ if (ctx->status & DEC_IEEE_854_Invalid_operation) { /* Leave only the error bits in the status flags. */ ctx->status &= DEC_IEEE_854_Invalid_operation; error (_("Cannot perform operation: %s"), decContextStatusToString (ctx)); } } /* Helper function to convert from libdecnumber's appropriate representation for computation to each size of decimal float. */ static void decimal_from_number (const decNumber *from, gdb_byte *to, int len) { decContext set; set_decnumber_context (&set, len); switch (len) { case 4: decimal32FromNumber ((decimal32 *) to, from, &set); break; case 8: decimal64FromNumber ((decimal64 *) to, from, &set); break; case 16: decimal128FromNumber ((decimal128 *) to, from, &set); break; } } /* Helper function to convert each size of decimal float to libdecnumber's appropriate representation for computation. */ static void decimal_to_number (const gdb_byte *from, int len, decNumber *to) { switch (len) { case 4: decimal32ToNumber ((decimal32 *) from, to); break; case 8: decimal64ToNumber ((decimal64 *) from, to); break; case 16: decimal128ToNumber ((decimal128 *) from, to); break; default: error (_("Unknown decimal floating point type.")); break; } } /* Convert decimal type to its string representation. LEN is the length of the decimal type, 4 bytes for decimal32, 8 bytes for decimal64 and 16 bytes for decimal128. */ std::string decimal_to_string (const gdb_byte *decbytes, int len, enum bfd_endian byte_order) { gdb_byte dec[16]; match_endianness (decbytes, len, byte_order, dec); std::string result; result.resize (MAX_DECIMAL_STRING); switch (len) { case 4: decimal32ToString ((decimal32 *) dec, &result[0]); break; case 8: decimal64ToString ((decimal64 *) dec, &result[0]); break; case 16: decimal128ToString ((decimal128 *) dec, &result[0]); break; default: error (_("Unknown decimal floating point type.")); break; } return result; } /* Convert the string form of a decimal value to its decimal representation. LEN is the length of the decimal type, 4 bytes for decimal32, 8 bytes for decimal64 and 16 bytes for decimal128. */ bool decimal_from_string (gdb_byte *decbytes, int len, enum bfd_endian byte_order, std::string string) { decContext set; gdb_byte dec[16]; set_decnumber_context (&set, len); switch (len) { case 4: decimal32FromString ((decimal32 *) dec, string.c_str (), &set); break; case 8: decimal64FromString ((decimal64 *) dec, string.c_str (), &set); break; case 16: decimal128FromString ((decimal128 *) dec, string.c_str (), &set); break; default: error (_("Unknown decimal floating point type.")); break; } match_endianness (dec, len, byte_order, decbytes); /* Check for errors in the DFP operation. */ decimal_check_errors (&set); return true; } /* Converts a LONGEST to a decimal float of specified LEN bytes. */ void decimal_from_longest (LONGEST from, gdb_byte *to, int len, enum bfd_endian byte_order) { gdb_byte dec[16]; decNumber number; if ((int32_t) from != from) /* libdecnumber can convert only 32-bit integers. */ error (_("Conversion of large integer to a " "decimal floating type is not supported.")); decNumberFromInt32 (&number, (int32_t) from); decimal_from_number (&number, dec, len); match_endianness (dec, len, byte_order, to); } /* Converts a ULONGEST to a decimal float of specified LEN bytes. */ void decimal_from_ulongest (ULONGEST from, gdb_byte *to, int len, enum bfd_endian byte_order) { gdb_byte dec[16]; decNumber number; if ((uint32_t) from != from) /* libdecnumber can convert only 32-bit integers. */ error (_("Conversion of large integer to a " "decimal floating type is not supported.")); decNumberFromUInt32 (&number, (uint32_t) from); decimal_from_number (&number, dec, len); match_endianness (dec, len, byte_order, to); } /* Converts a decimal float of LEN bytes to a LONGEST. */ LONGEST decimal_to_longest (const gdb_byte *from, int len, enum bfd_endian byte_order) { /* libdecnumber has a function to convert from decimal to integer, but it doesn't work when the decimal number has a fractional part. */ std::string str = decimal_to_string (from, len, byte_order); return strtoll (str.c_str (), NULL, 10); } /* Converts a value of a float type to a decimal float of specified LEN bytes. This is an ugly way to do the conversion, but libdecnumber does not offer a direct way to do it. */ void decimal_from_doublest (DOUBLEST from, gdb_byte *to, int len, enum bfd_endian byte_order) { std::string str = string_printf ("%.30" DOUBLEST_PRINT_FORMAT, from); decimal_from_string (to, len, byte_order, str); } /* Converts a decimal float of LEN bytes to a double value. */ DOUBLEST decimal_to_doublest (const gdb_byte *from, int len, enum bfd_endian byte_order) { /* This is an ugly way to do the conversion, but libdecnumber does not offer a direct way to do it. */ std::string str = decimal_to_string (from, len, byte_order); return strtod (str.c_str (), NULL); } /* Perform operation OP with operands X and Y with sizes LEN_X and LEN_Y and byte orders BYTE_ORDER_X and BYTE_ORDER_Y, and store value in RESULT with size LEN_RESULT and byte order BYTE_ORDER_RESULT. */ void decimal_binop (enum exp_opcode op, const gdb_byte *x, int len_x, enum bfd_endian byte_order_x, const gdb_byte *y, int len_y, enum bfd_endian byte_order_y, gdb_byte *result, int len_result, enum bfd_endian byte_order_result) { decContext set; decNumber number1, number2, number3; gdb_byte dec1[16], dec2[16], dec3[16]; match_endianness (x, len_x, byte_order_x, dec1); match_endianness (y, len_y, byte_order_y, dec2); decimal_to_number (dec1, len_x, &number1); decimal_to_number (dec2, len_y, &number2); set_decnumber_context (&set, len_result); switch (op) { case BINOP_ADD: decNumberAdd (&number3, &number1, &number2, &set); break; case BINOP_SUB: decNumberSubtract (&number3, &number1, &number2, &set); break; case BINOP_MUL: decNumberMultiply (&number3, &number1, &number2, &set); break; case BINOP_DIV: decNumberDivide (&number3, &number1, &number2, &set); break; case BINOP_EXP: decNumberPower (&number3, &number1, &number2, &set); break; default: internal_error (__FILE__, __LINE__, _("Unknown decimal floating point operation.")); break; } /* Check for errors in the DFP operation. */ decimal_check_errors (&set); decimal_from_number (&number3, dec3, len_result); match_endianness (dec3, len_result, byte_order_result, result); } /* Returns true if X (which is LEN bytes wide) is the number zero. */ int decimal_is_zero (const gdb_byte *x, int len, enum bfd_endian byte_order) { decNumber number; gdb_byte dec[16]; match_endianness (x, len, byte_order, dec); decimal_to_number (dec, len, &number); return decNumberIsZero (&number); } /* Compares two numbers numerically. If X is less than Y then the return value will be -1. If they are equal, then the return value will be 0. If X is greater than the Y then the return value will be 1. */ int decimal_compare (const gdb_byte *x, int len_x, enum bfd_endian byte_order_x, const gdb_byte *y, int len_y, enum bfd_endian byte_order_y) { decNumber number1, number2, result; decContext set; gdb_byte dec1[16], dec2[16]; int len_result; match_endianness (x, len_x, byte_order_x, dec1); match_endianness (y, len_y, byte_order_y, dec2); decimal_to_number (dec1, len_x, &number1); decimal_to_number (dec2, len_y, &number2); /* Perform the comparison in the larger of the two sizes. */ len_result = len_x > len_y ? len_x : len_y; set_decnumber_context (&set, len_result); decNumberCompare (&result, &number1, &number2, &set); /* Check for errors in the DFP operation. */ decimal_check_errors (&set); if (decNumberIsNaN (&result)) error (_("Comparison with an invalid number (NaN).")); else if (decNumberIsZero (&result)) return 0; else if (decNumberIsNegative (&result)) return -1; else return 1; } /* Convert a decimal value from a decimal type with LEN_FROM bytes to a decimal type with LEN_TO bytes. */ void decimal_convert (const gdb_byte *from, int len_from, enum bfd_endian byte_order_from, gdb_byte *to, int len_to, enum bfd_endian byte_order_to) { decNumber number; gdb_byte dec[16]; match_endianness (from, len_from, byte_order_from, dec); decimal_to_number (dec, len_from, &number); decimal_from_number (&number, dec, len_to); match_endianness (dec, len_to, byte_order_to, to); }