cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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fsub.c (869B)

      1// SPDX-License-Identifier: GPL-2.0
      2#include <linux/types.h>
      3#include <linux/errno.h>
      4#include <linux/uaccess.h>
      5
      6#include <asm/sfp-machine.h>
      7#include <math-emu/soft-fp.h>
      8#include <math-emu/double.h>
      9
     10int
     11fsub(void *frD, void *frA, void *frB)
     12{
     13	FP_DECL_D(A);
     14	FP_DECL_D(B);
     15	FP_DECL_D(R);
     16	FP_DECL_EX;
     17
     18#ifdef DEBUG
     19	printk("%s: %p %p %p\n", __func__, frD, frA, frB);
     20#endif
     21
     22	FP_UNPACK_DP(A, frA);
     23	FP_UNPACK_DP(B, frB);
     24
     25#ifdef DEBUG
     26	printk("A: %ld %lu %lu %ld (%ld)\n", A_s, A_f1, A_f0, A_e, A_c);
     27	printk("B: %ld %lu %lu %ld (%ld)\n", B_s, B_f1, B_f0, B_e, B_c);
     28#endif
     29
     30	if (B_c != FP_CLS_NAN)
     31		B_s ^= 1;
     32
     33	if (A_s != B_s && A_c == FP_CLS_INF && B_c == FP_CLS_INF)
     34		FP_SET_EXCEPTION(EFLAG_VXISI);
     35
     36	FP_ADD_D(R, A, B);
     37
     38#ifdef DEBUG
     39	printk("D: %ld %lu %lu %ld (%ld)\n", R_s, R_f1, R_f0, R_e, R_c);
     40#endif
     41
     42	__FP_PACK_D(frD, R);
     43
     44	return FP_CUR_EXCEPTIONS;
     45}