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Add dynamic mode change by writing to $d030 #8

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Add dynamic mode change by writing to $d030 #8

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f21e26d
Add dynamic mode change by writing to $d030
Nov 12, 2021
0a84750
This would prevent writes to byte 0x02
Nov 14, 2021
24f4dff
Use current_p to test for which ROM and IO mode currently is in effec…
Nov 14, 2021
43075bc
Bah, did not compile test, fixed defines and if() logic
Nov 14, 2021
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48 changes: 26 additions & 22 deletions MCL64/SourceCode/MCL64.ino
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Original file line number Diff line number Diff line change
Expand Up @@ -136,6 +136,7 @@ uint8_t direct_nmi=0;
uint8_t assert_sync=0;
uint8_t global_temp=0;
uint8_t last_access_internal_RAM=0;
uint8_t mode=1;

uint16_t register_pc=0;
uint16_t current_address=0;
Expand All @@ -162,8 +163,8 @@ uint8_t CART_LOW_ROM[0x2000];
// When set to 1 it will remove the unnecessary 6502 bus fetches, reads, and writes
// Set to 0 for cycle-accurate mode
//
#define SPEEDUP 1
// #define SPEEDUP 1 - changed to dynamic value

// ------------------------------------------------------------------------------
// ------------------------------------------------------------------------------

Expand Down Expand Up @@ -242,15 +243,15 @@ void setup() {
// ----------------------------------------------------------
inline uint8_t internal_address_check(uint16_t local_address) {

if ( (local_address > 0x0001 ) && (local_address <= 0x03FF) ) return 0x1; // Zero-Page up to video
if ( (local_address > 0x0001 ) && (local_address <= 0x03FF) ) return mode; // Zero-Page up to video
if ( (local_address >= 0x0400) && (local_address <= 0x07FF) ) return 0x1; // C64 Video Memory
if ( (local_address >= 0x0800) && (local_address <= 0x9FFF) ) return 0x1; // C64 RAM
if ( (local_address >= 0xA000) && (local_address <= 0xBFFF) ) return 0x1; // C64 BASIC ROM
if ( (local_address >= 0xC000) && (local_address <= 0xCFFF) ) return 0x1; // C64 RAM
if ( (local_address >= 0x0800) && (local_address <= 0x9FFF) ) return mode; // C64 RAM
if ( (local_address >= 0xA000) && (local_address <= 0xBFFF) ) return mode; // C64 BASIC ROM
if ( (local_address >= 0xC000) && (local_address <= 0xCFFF) ) return mode; // C64 RAM
//if ( (local_address >= 0xD000) && (local_address <= 0xDFFF) ) return 0x1; // C64 I/O
if ( (local_address >= 0xE000) && (local_address <= 0xE4FF) ) return 0x1; // C64 KERNAL ROM
if ( (local_address >= 0xE500) && (local_address <= 0xFF7F) ) return 0x1; // C64 KERNAL ROM
if ( (local_address >= 0xFF80) && (local_address <= 0xFFFF) ) return 0x1; // C64 KERNAL ROM
if ( (local_address >= 0xE000) && (local_address <= 0xE4FF) ) return mode; // C64 KERNAL ROM
if ( (local_address >= 0xE500) && (local_address <= 0xFF7F) ) return mode; // C64 KERNAL ROM
if ( (local_address >= 0xFF80) && (local_address <= 0xFFFF) ) return mode; // C64 KERNAL ROM

return 0x0;
}
Expand Down Expand Up @@ -476,6 +477,9 @@ inline void write_byte(uint16_t local_address , uint8_t local_write_data) {

wait_for_CLK_rising_edge();
digitalWriteFast(PIN_DATAOUT_OE_n, 0x1 );
}
if ( internal_address_check(local_address) == 0xd030) {
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probably here should be a check to see if I/O is enabled with current memory configuration

mode = ( local_write_data & 0x03 );
}
return;
}
Expand Down Expand Up @@ -547,15 +551,15 @@ uint8_t Fetch_ZeroPage() {
uint8_t Fetch_ZeroPage_X() {
uint16_t bal;
bal = Fetch_Immediate();
if (SPEEDUP==0) read_byte(register_pc+1);
if (mode==0) read_byte(register_pc+1);
effective_address = (0x00FF & (bal + register_x));
return read_byte(effective_address);
}

uint8_t Fetch_ZeroPage_Y() {
uint16_t bal;
bal = Fetch_Immediate();
if (SPEEDUP==0) read_byte(register_pc+1);
if (mode==0) read_byte(register_pc+1);
effective_address = (0x00FF & (bal + register_y));
return read_byte(effective_address);
}
Expand Down Expand Up @@ -587,7 +591,7 @@ uint8_t Fetch_Absolute_X(uint8_t page_cross_check) {
effective_address = bah + bal + register_x;
local_data = read_byte(effective_address );

if ( (SPEEDUP==0) && page_cross_check==1 && ( (0xFF00&effective_address) != (0xFF00&bah) ) ) {
if ( (mode==0) && page_cross_check==1 && ( (0xFF00&effective_address) != (0xFF00&bah) ) ) {
local_data = read_byte(effective_address );
}
return local_data;
Expand All @@ -602,7 +606,7 @@ uint8_t Fetch_Absolute_Y(uint8_t page_cross_check) {
effective_address = bah + bal + register_y;
local_data = read_byte(effective_address );

if ( (SPEEDUP==0) && page_cross_check==1 && ( (0xFF00&effective_address) != (0xFF00&bah) ) ) {
if ( (mode==0) && page_cross_check==1 && ( (0xFF00&effective_address) != (0xFF00&bah) ) ) {
local_data = read_byte(effective_address );
}
return local_data;
Expand Down Expand Up @@ -633,7 +637,7 @@ uint8_t Fetch_Indexed_Indirect_Y(uint8_t page_cross_check) {
effective_address = bah + bal + register_y;
local_data = read_byte(effective_address);

if ( (SPEEDUP==0) && page_cross_check==1 && ((0xFF00&effective_address) != (0xFF00&bah)) ) {
if ( (mode==0) && page_cross_check==1 && ((0xFF00&effective_address) != (0xFF00&bah)) ) {
local_data = read_byte(effective_address);
}
return local_data;
Expand All @@ -655,14 +659,14 @@ void Write_Absolute(uint8_t local_data) {

void Write_ZeroPage_X(uint8_t local_data) {
effective_address = Fetch_Immediate();
if (SPEEDUP==0) read_byte(effective_address);
if (mode==0) read_byte(effective_address);
write_byte( (0x00FF&(effective_address + register_x)) , local_data );
return;
}

void Write_ZeroPage_Y(uint8_t local_data) {
effective_address = Fetch_Immediate();
if (SPEEDUP==0) read_byte(effective_address);
if (mode==0) read_byte(effective_address);
write_byte( (0x00FF&(effective_address + register_y)) , local_data );
return;
}
Expand All @@ -673,7 +677,7 @@ void Write_Absolute_X(uint8_t local_data) {
bal = Fetch_Immediate();
bah = Fetch_Immediate()<<8;
effective_address = bal + bah + register_x;
if (SPEEDUP==0) read_byte(effective_address);
if (mode==0) read_byte(effective_address);
write_byte(effective_address , local_data );
return;
}
Expand All @@ -686,7 +690,7 @@ void Write_Absolute_Y(uint8_t local_data) {
effective_address = bal + bah + register_y;
read_byte(effective_address);

if (SPEEDUP==0) {
if (mode==0) {
if ( (0xFF00&effective_address) != (0xFF00&bah) ) {
read_byte(effective_address);
}
Expand Down Expand Up @@ -716,14 +720,14 @@ void Write_Indexed_Indirect_Y(uint8_t local_data) {
bal = read_byte(ial);
bah = read_byte(ial+1)<<8;
effective_address = bah + bal + register_y;
if (SPEEDUP==0) read_byte(effective_address);
if (mode==0) read_byte(effective_address);
write_byte(effective_address , local_data );
return;
}

void Double_WriteBack(uint8_t local_data) {
write_byte(effective_address , local_data);
if (SPEEDUP==0) write_byte(effective_address , local_data);
if (mode==0) write_byte(effective_address , local_data);
return;
}

Expand Down Expand Up @@ -1401,7 +1405,7 @@ void Branch_Taken() {
effective_address = Sign_Extend16(Fetch_Immediate());
effective_address = (register_pc+1) + effective_address;

if (SPEEDUP==0) {
if (mode==0) {
if ( (0xFF00&register_pc) == (0xFF00&effective_address) ) { Fetch_Immediate(); } // Page boundary not crossed
else { Fetch_Immediate(); Fetch_Immediate(); } // Page boundary crossed
}
Expand Down Expand Up @@ -1490,7 +1494,7 @@ void opcode_0x60() {
pcl = pop();
pch = pop()<<8;
register_pc = pch+pcl+1;
if (SPEEDUP==0) read_byte(register_pc);
if (mode==0) read_byte(register_pc);
assert_sync=1;
start_read(register_pc);
return ;
Expand Down