1 /* Copyright (C) 2008 The Android Open Source Project 2 * 3 * Licensed under the Apache License, Version 2.0 (the "License"); 4 * you may not use this file except in compliance with the License. 5 * You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software 10 * distributed under the License is distributed on an "AS IS" BASIS, 11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 * See the License for the specific language governing permissions and 13 * limitations under the License. 14 */ 15 16 /* 17 * File: OP_MUL_LONG.S 18 * 19 * Code: 64-bit integer multiply 20 * 21 * For: mul-long 22 * 23 * Description: Multiply two source registers and store the 24 * result in a destination register. 25 * 26 * Format: AA|op CC|BB (23x) 27 * 28 * Syntax: op vAA, vBB, vCC 29 */ 30 31 /* 32 * Signed 64-bit integer multiply. 33 * 34 * Consider WXxYZ (r1r0 x r3r2) with a long multiply: 35 * WX 36 * x YZ 37 * -------- 38 * ZW ZX 39 * YW YX 40 * 41 * The low word of the result holds ZX, the high word holds 42 * (ZW+YX) + (the high overflow from ZX). YW doesn't matter because 43 * it doesn't fit in the low 64 bits. 44 */ 45 46 movl rINST, -4(%esp) # -4(%esp)<- AA+ 47 FETCH_BB 1, rINST # rINST<- BB 48 FETCH_CC 1, %edx # %edx<- CC 49 jmp .L${opcode}_finish 50 %break 51 52 /* 53 * X = (rFP, rINST, 4) 54 * W = 4(rFP, rINST, 4) 55 * Z = (rFP, %edx, 4) 56 * Y = 4(rFP, %edx, 4) 57 */ 58 59 .L${opcode}_finish: 60 movl 4(rFP, rINST, 4), %ecx # %ecx<- W 61 imull (rFP, %edx, 4), %ecx # %ecx<- WxZ 62 mov 4(rFP, %edx, 4), %eax # %ecx<- Y 63 imull (rFP, rINST, 4), %eax # %eax<- XxY 64 addl %eax, %ecx # %ecx<- (WZ + XY) 65 movl (rFP, %edx, 4), %eax # %eax<- Z 66 mull (rFP, rINST, 4) # %edx:eax<- XZ 67 movzbl -4(%esp), rINST # rINST<- AA 68 addl %edx, %ecx # %ecx<- carry + (WZ + XY) 69 movl %ecx, 4(rFP, rINST, 4) # vAA+1<- results hi 70 movl %eax, (rFP, rINST, 4) # vAA<- results lo 71 FINISH 2 # jump to next instruction 72
