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https://github.com/netwide-assembler/nasm.git
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5f3bfee708
Consolidated two separate but similar functions in nasm and ndisasm into a commonly linked source code. To encode and decode the compressed displacement (disp8*N) for EVEX, N value should be derived using various conditions. Signed-off-by: Jin Kyu Song <jin.kyu.song@intel.com>
132 lines
3.9 KiB
C
132 lines
3.9 KiB
C
/* ----------------------------------------------------------------------- *
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*
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* Copyright 1996-2013 The NASM Authors - All Rights Reserved
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* See the file AUTHORS included with the NASM distribution for
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* the specific copyright holders.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following
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* conditions are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials provided
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* with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
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* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* ----------------------------------------------------------------------- */
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/*
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* disp8.c : Contains a common logic for EVEX compressed displacement
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*/
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#include "disp8.h"
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/*
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* Find N value for compressed displacement (disp8 * N)
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*/
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uint8_t get_disp8N(insn *ins)
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{
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const uint8_t fv_n[2][2][VLMAX] = {{{16, 32, 64}, {4, 4, 4}},
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{{16, 32, 64}, {8, 8, 8}}};
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const uint8_t hv_n[2][VLMAX] = {{8, 16, 32}, {4, 4, 4}};
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const uint8_t dup_n[VLMAX] = {8, 32, 64};
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bool evex_b = (ins->evex_p[2] & EVEX_P2B) >> 4;
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enum ttypes tuple = ins->evex_tuple;
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enum vectlens vectlen = (ins->evex_p[2] & EVEX_P2LL) >> 5;
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bool evex_w = (ins->evex_p[1] & EVEX_P1W) >> 7;
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uint8_t n = 0;
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switch(tuple) {
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case FV:
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n = fv_n[evex_w][evex_b][vectlen];
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break;
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case HV:
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n = hv_n[evex_b][vectlen];
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break;
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case FVM:
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/* 16, 32, 64 for VL 128, 256, 512 respectively*/
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n = 1 << (vectlen + 4);
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break;
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case T1S8: /* N = 1 */
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case T1S16: /* N = 2 */
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n = tuple - T1S8 + 1;
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break;
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case T1S:
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/* N = 4 for 32bit, 8 for 64bit */
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n = evex_w ? 8 : 4;
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break;
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case T1F32:
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case T1F64:
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/* N = 4 for 32bit, 8 for 64bit */
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n = (tuple == T1F32 ? 4 : 8);
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break;
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case T2:
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case T4:
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case T8:
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if (vectlen + 7 <= (evex_w + 5) + (tuple - T2 + 1))
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n = 0;
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else
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n = 1 << (tuple - T2 + evex_w + 3);
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break;
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case HVM:
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case QVM:
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case OVM:
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n = 1 << (OVM - tuple + vectlen + 1);
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break;
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case M128:
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n = 16;
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break;
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case DUP:
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n = dup_n[vectlen];
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break;
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default:
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break;
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}
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return n;
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}
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/*
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* Check if offset is a multiple of N with corresponding tuple type
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* if Disp8*N is available, compressed displacement is stored in compdisp
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*/
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bool is_disp8n(operand *input, insn *ins, int8_t *compdisp)
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{
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int32_t off = input->offset;
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uint8_t n;
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int32_t disp8;
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n = get_disp8N(ins);
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if (n && !(off & (n - 1))) {
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disp8 = off / n;
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/* if it fits in Disp8 */
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if (disp8 >= -128 && disp8 <= 127) {
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*compdisp = disp8;
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return true;
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}
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}
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*compdisp = 0;
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return false;
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}
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