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248 lines
6.0 KiB
C
248 lines
6.0 KiB
C
//
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// main.c
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// 6502
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//
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// Created by Tamas Rudnai on 7/14/19.
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// Copyright © 2019, 2020 Tamas Rudnai. All rights reserved.
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//
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// This file is part of Steve ][ -- The Apple ][ Emulator.
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//
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// Steve ][ is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// Steve ][ is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with Steve ][. If not, see <https://www.gnu.org/licenses/>.
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//
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// Documentations:
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//
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// http://nesdev.com/6502_cpu.txt
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// http://www.oxyron.de/html/opcodes02.html
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// https://macgui.com/kb/article/46
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// https://www.masswerk.at/6502/6502_instruction_set.html
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//
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#include <string.h>
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#include <stdlib.h>
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#include "6502_bp.h"
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/// Array of addresses of active breakpoints
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/// @note DEBUG_MAX_BREAKPOINTS controls its size
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uint16_t breakpoints[DEBUG_MAX_BREAKPOINTS];
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/// Index of last valid breakpoint element in the array
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int bp_last_idx = 0;
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/// Index of current breapoint
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/// @note It is more like a temporary variable
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int bp_idx = 0;
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/// Swap 2 items
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/// @param a Pointer of first item
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/// @param b Pointer to second item
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static inline void swap(uint16_t * a, uint16_t * b) {
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uint16_t temp = *a;
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*a = *b;
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*b = temp;
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}
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/// m6502_dbg_bp_sort
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/// Sort breakpoint array ascending
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/// @param arr Breakpoint array
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/// @param first Index of first element to sort
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/// @param last Index of last element to sort
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void m6502_dbg_bp_sort( uint16_t arr[], int first, int last ) {
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if ( first < last ) {
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uint16_t pivot = first; // (first + last) / 2;
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int i = first;
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int j = last;
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while ( i < j ) {
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while ( arr[i] <= arr[pivot] && i < last ) {
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i++;
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}
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while ( arr[j] > arr[pivot] && j > first ) {
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j--;
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}
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if ( i < j ) {
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swap(breakpoints + i, breakpoints + j);
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}
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}
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swap(breakpoints + pivot, breakpoints + j);
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if (j > first) {
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m6502_dbg_bp_sort( arr, first, j - 1 );
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}
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if (j < last) {
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m6502_dbg_bp_sort( arr, j + 1, last );
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}
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}
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}
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/// A binary search function. It returns
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/// @param arr Breakpoint array
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/// @param l Left index
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/// @param r Right index
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/// @param addr Address to search for
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/// @return lIndex of addr in Breakpoints, otherwise -1
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int m6502_dbg_bp_search(uint16_t arr[], int l, int r, uint16_t addr) {
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while ( r >= l ) {
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int mid = (l + r) / 2;
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// found it
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if (arr[mid] == addr) {
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return mid;
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}
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// maybe in the left side?
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else if (arr[mid] > addr) {
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r = mid - 1;
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}
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// maybe in the right side?
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else {
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l = mid + 1;
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}
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}
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// addr not found
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return -1;
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}
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/// Get index of the last BP
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/// @param i Current last index
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/// @return Index of the last breakpoint or 0 if non
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int m6502_dbg_bp_get_last(int i) {
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for(; i >= 0; i--) {
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if ( breakpoints[i] ) {
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return i;
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}
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}
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// index should be 0 if there is no any BPs
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return 0;
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}
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/// Get first valid BP
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/// @return addr of BP or 0 if non
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uint16_t m6502_dbg_bp_get_next() {
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while ( bp_idx < bp_last_idx ) {
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uint16_t addr = breakpoints[++bp_idx];
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if (addr) {
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return addr;
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}
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}
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// no empty slots
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return 0;
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}
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/// Get first valid BP
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/// @return addr of BP or 0 if non
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uint16_t m6502_dbg_bp_get_first() {
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bp_idx = -1;
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return m6502_dbg_bp_get_next();
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}
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/// m6502_dbg_bp_get_empty
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/// Get an empty slot in the bp storage
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/// @return Index of the empty breakpoint or -1 if error
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int m6502_dbg_bp_get_empty() {
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for (int i = 0; i < DEBUG_MAX_BREAKPOINTS; i++) {
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if ( breakpoints[i] == 0 ) {
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return i;
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}
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}
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// no empty slots
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return -1;
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}
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/// Get first not empty slot in the bp storage
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/// @return Index of the empty breakpoint or -1 if error
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int m6502_dbg_bp_get_not_empty() {
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for (int i = 0; i < DEBUG_MAX_BREAKPOINTS; i++) {
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if ( breakpoints[i] ) {
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return i;
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}
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}
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// no empty slots
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return -1;
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}
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/// Move array down to eliminate leading zeros
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/// @note: Array must be sorted before this!
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void m6502_dbg_bp_compact() {
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int i = m6502_dbg_bp_get_not_empty();
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memcpy(breakpoints, breakpoints + i, bp_last_idx * sizeof(uint16_t));
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memset(breakpoints + bp_last_idx, 0, (DEBUG_MAX_BREAKPOINTS - bp_last_idx) * sizeof(uint16_t));
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bp_last_idx = m6502_dbg_bp_get_last(bp_last_idx);
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}
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/// Check if BP exists
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/// @param addr Address to check
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/// @return 1 (true) if exists, 0 (false) if not
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_Bool m6502_dbg_bp_is_exists(uint16_t addr) {
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if (addr) {
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int i = m6502_dbg_bp_search(breakpoints, 0, bp_last_idx, addr);
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return i >= 0;
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}
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else return 0;
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}
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/// Add breakpoint
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/// @param addr Address to add
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/// @return Index of breakpoint or -1 if error
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int m6502_dbg_bp_add(uint16_t addr) {
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if (bp_last_idx < DEBUG_MAX_BREAKPOINTS - 1) {
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breakpoints[++bp_last_idx] = addr;
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m6502_dbg_bp_sort(breakpoints, 0, bp_last_idx);
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return bp_last_idx;
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}
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// no empty slots
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return -1;
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}
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/// Remove a breakpoint
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/// @param addr address to remove
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void m6502_dbg_bp_del(uint16_t addr) {
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int i = m6502_dbg_bp_search(breakpoints, 0, bp_last_idx, addr);
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if (i >= 0) {
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breakpoints[i] = 0;
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m6502_dbg_bp_sort(breakpoints, 0, bp_last_idx);
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m6502_dbg_bp_compact();
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}
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}
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/// Delete all breakpoints
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void m6502_dbg_bp_del_all(void) {
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bp_idx = 0;
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memset(breakpoints, 0, sizeof(breakpoints));
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}
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/// Initialize Breakpoints
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void m6502_dbg_init(void) {
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m6502_dbg_bp_del_all();
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}
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