|
Last change
on this file since 357 was 2, checked in by Rick van der Zwet, 15 years ago |
|
Initial import of data of old repository ('data') worth keeping (e.g. tracking
means of URL access statistics)
|
-
Property svn:executable
set to
*
|
|
File size:
1.7 KB
|
| Line | |
|---|
| 1 | /* Author : Rick van der Zwet
|
|---|
| 2 | * S-number : 0433373
|
|---|
| 3 | * Version : $Id: alu.c 364 2007-12-03 07:23:37Z rick $
|
|---|
| 4 | * Copyright : FreeBSD Licence
|
|---|
| 5 | * Description : ALU unit
|
|---|
| 6 | */
|
|---|
| 7 |
|
|---|
| 8 | #include <stdlib.h>
|
|---|
| 9 | #include <stdio.h>
|
|---|
| 10 | #include <sysexits.h>
|
|---|
| 11 | #include "alu.h"
|
|---|
| 12 |
|
|---|
| 13 | word
|
|---|
| 14 | alu_sra(const word in1, const word in2)
|
|---|
| 15 | {
|
|---|
| 16 | word out = 0;
|
|---|
| 17 | out = in1 >> in2;
|
|---|
| 18 | /* Find out wether high order bit was set */
|
|---|
| 19 | if (in1 >> (BITSIZE(out) - 1) == 0x1) {
|
|---|
| 20 | /* Set bit in2 till high-order to 1 */
|
|---|
| 21 | int i = BITSIZE(out) - in2;
|
|---|
| 22 | for (; i < BITSIZE(out); i++)
|
|---|
| 23 | out = out | (1 << i);
|
|---|
| 24 | }
|
|---|
| 25 | return (out);
|
|---|
| 26 | }
|
|---|
| 27 |
|
|---|
| 28 | word
|
|---|
| 29 | alu(word in1, word in2, alu_control_t action)
|
|---|
| 30 | {
|
|---|
| 31 | word out = 0;
|
|---|
| 32 | switch (action) {
|
|---|
| 33 | case ADD:
|
|---|
| 34 | out = in1 + in2;
|
|---|
| 35 | break;
|
|---|
| 36 | case AND:
|
|---|
| 37 | out = in1 & in2;
|
|---|
| 38 | break;
|
|---|
| 39 | case NOR:
|
|---|
| 40 | out = ~(in1 | in2);
|
|---|
| 41 | break;
|
|---|
| 42 | case OR:
|
|---|
| 43 | out = in1 | in2;
|
|---|
| 44 | break;
|
|---|
| 45 | case PassS1:
|
|---|
| 46 | out = in1;
|
|---|
| 47 | break;
|
|---|
| 48 | case PassS2:
|
|---|
| 49 | out = in2;
|
|---|
| 50 | break;
|
|---|
| 51 | case SLL:
|
|---|
| 52 | out = in1 << in2;
|
|---|
| 53 | break;
|
|---|
| 54 | case SRA:
|
|---|
| 55 | out = alu_sra(in1, in2);
|
|---|
| 56 | break;
|
|---|
| 57 | case SRL:
|
|---|
| 58 | out = in1 >> in2;
|
|---|
| 59 | break;
|
|---|
| 60 | case SUB:
|
|---|
| 61 | out = in1 - in2;
|
|---|
| 62 | break;
|
|---|
| 63 | case XOR:
|
|---|
| 64 | out = in1 ^ in2;
|
|---|
| 65 | break;
|
|---|
| 66 | default:
|
|---|
| 67 | fprintf(stderr,"Requested alu-action not implemented\n");
|
|---|
| 68 | exit(EX_SOFTWARE);
|
|---|
| 69 | break;
|
|---|
| 70 | };
|
|---|
| 71 |
|
|---|
| 72 | /* Set signals */
|
|---|
| 73 | if (out < 0) {
|
|---|
| 74 | zero = FALSE;
|
|---|
| 75 | negative = TRUE;
|
|---|
| 76 | } else if (out == 0) {
|
|---|
| 77 | zero = TRUE;
|
|---|
| 78 | negative = FALSE;
|
|---|
| 79 | } else {
|
|---|
| 80 | zero = FALSE;
|
|---|
| 81 | negative = FALSE;
|
|---|
| 82 | }
|
|---|
| 83 |
|
|---|
| 84 | return(out);
|
|---|
| 85 | }
|
|---|
Note:
See
TracBrowser
for help on using the repository browser.
