^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*---------------------------------------------------------------------------+
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) | reg_mul.c |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) | |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) | Multiply one FPU_REG by another, put the result in a destination FPU_REG. |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) | |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) | Copyright (C) 1992,1993,1997 |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) | E-mail billm@suburbia.net |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) | |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) | Returns the tag of the result if no exceptions or errors occurred. |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) | |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) +---------------------------------------------------------------------------*/
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) /*---------------------------------------------------------------------------+
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) | The destination may be any FPU_REG, including one of the source FPU_REGs. |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) +---------------------------------------------------------------------------*/
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) #include "fpu_emu.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) #include "exception.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) #include "reg_constant.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) #include "fpu_system.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) Multiply two registers to give a register result.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) The sources are st(deststnr) and (b,tagb,signb).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) The destination is st(deststnr).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) /* This routine must be called with non-empty source registers */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) int FPU_mul(FPU_REG const *b, u_char tagb, int deststnr, int control_w)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) FPU_REG *a = &st(deststnr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) FPU_REG *dest = a;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) u_char taga = FPU_gettagi(deststnr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) u_char saved_sign = getsign(dest);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) u_char sign = (getsign(a) ^ getsign(b));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) int tag;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) if (!(taga | tagb)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) /* Both regs Valid, this should be the most common case. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) tag =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) FPU_u_mul(a, b, dest, control_w, sign,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) exponent(a) + exponent(b));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) if (tag < 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) setsign(dest, saved_sign);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) return tag;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) FPU_settagi(deststnr, tag);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) return tag;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) if (taga == TAG_Special)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) taga = FPU_Special(a);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) if (tagb == TAG_Special)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) tagb = FPU_Special(b);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) if (((taga == TAG_Valid) && (tagb == TW_Denormal))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) || ((taga == TW_Denormal) && (tagb == TAG_Valid))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) || ((taga == TW_Denormal) && (tagb == TW_Denormal))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) FPU_REG x, y;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) if (denormal_operand() < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) return FPU_Exception;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) FPU_to_exp16(a, &x);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) FPU_to_exp16(b, &y);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) tag = FPU_u_mul(&x, &y, dest, control_w, sign,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) exponent16(&x) + exponent16(&y));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) if (tag < 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) setsign(dest, saved_sign);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) return tag;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) FPU_settagi(deststnr, tag);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) return tag;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) } else if ((taga <= TW_Denormal) && (tagb <= TW_Denormal)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) if (((tagb == TW_Denormal) || (taga == TW_Denormal))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) && (denormal_operand() < 0))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) return FPU_Exception;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) /* Must have either both arguments == zero, or
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) one valid and the other zero.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) The result is therefore zero. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) /* The 80486 book says that the answer is +0, but a real
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) 80486 behaves this way.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) IEEE-754 apparently says it should be this way. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) setsign(dest, sign);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) return TAG_Zero;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) /* Must have infinities, NaNs, etc */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) else if ((taga == TW_NaN) || (tagb == TW_NaN)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) return real_2op_NaN(b, tagb, deststnr, &st(0));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) } else if (((taga == TW_Infinity) && (tagb == TAG_Zero))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) || ((tagb == TW_Infinity) && (taga == TAG_Zero))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) return arith_invalid(deststnr); /* Zero*Infinity is invalid */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) } else if (((taga == TW_Denormal) || (tagb == TW_Denormal))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) && (denormal_operand() < 0)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) return FPU_Exception;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) } else if (taga == TW_Infinity) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) FPU_copy_to_regi(a, TAG_Special, deststnr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) setsign(dest, sign);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) return TAG_Special;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) } else if (tagb == TW_Infinity) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) FPU_copy_to_regi(b, TAG_Special, deststnr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) setsign(dest, sign);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) return TAG_Special;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) #ifdef PARANOID
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) EXCEPTION(EX_INTERNAL | 0x102);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) return FPU_Exception;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) #endif /* PARANOID */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) }
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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