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Set the interupt flag after writing the status register to the stack #42

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17 changes: 13 additions & 4 deletions Part #3 - Buses, Rams, Roms & Mappers/olc6502.cpp
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -68,7 +68,7 @@

Author
~~~~~~
David Barr, aka javidx9, �OneLoneCoder 2019
David Barr, aka javidx9, �OneLoneCoder 2019
*/

#include "olc6502.h"
Expand Down Expand Up @@ -208,10 +208,13 @@ void olc6502::irq()
// Then Push the status register to the stack
SetFlag(B, 0);
SetFlag(U, 1);
SetFlag(I, 1);
write(0x0100 + stkp, status);
stkp--;

// After writing to the stack, set the Interupt flag to 1
// to prevent other interrupts
SetFlag(I, 1);

// Read new program counter location from fixed address
addr_abs = 0xFFFE;
uint16_t lo = read(addr_abs + 0);
Expand All @@ -236,10 +239,13 @@ void olc6502::nmi()

SetFlag(B, 0);
SetFlag(U, 1);
SetFlag(I, 1);
write(0x0100 + stkp, status);
stkp--;

// After writing to the stack, set the Interupt flag to 1
// to prevent other interrupts
SetFlag(I, 1);

addr_abs = 0xFFFA;
uint16_t lo = read(addr_abs + 0);
uint16_t hi = read(addr_abs + 1);
Expand Down Expand Up @@ -894,7 +900,6 @@ uint8_t olc6502::BRK()
{
pc++;

SetFlag(I, 1);
write(0x0100 + stkp, (pc >> 8) & 0x00FF);
stkp--;
write(0x0100 + stkp, pc & 0x00FF);
Expand All @@ -905,6 +910,10 @@ uint8_t olc6502::BRK()
stkp--;
SetFlag(B, 0);

// After writing to the stack, set the Interupt flag to 1
// to prevent other interrupts
SetFlag(I, 1);

pc = (uint16_t)read(0xFFFE) | ((uint16_t)read(0xFFFF) << 8);
return 0;
}
Expand Down
17 changes: 13 additions & 4 deletions Part #4 - PPU Backgrounds/olc6502.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -68,7 +68,7 @@

Author
~~~~~~
David Barr, aka javidx9, �OneLoneCoder 2019
David Barr, aka javidx9, �OneLoneCoder 2019
*/

#include "olc6502.h"
Expand Down Expand Up @@ -208,10 +208,13 @@ void olc6502::irq()
// Then Push the status register to the stack
SetFlag(B, 0);
SetFlag(U, 1);
SetFlag(I, 1);
write(0x0100 + stkp, status);
stkp--;

// After writing to the stack, set the Interupt flag to 1
// to prevent other interrupts
SetFlag(I, 1);

// Read new program counter location from fixed address
addr_abs = 0xFFFE;
uint16_t lo = read(addr_abs + 0);
Expand All @@ -236,10 +239,13 @@ void olc6502::nmi()

SetFlag(B, 0);
SetFlag(U, 1);
SetFlag(I, 1);
write(0x0100 + stkp, status);
stkp--;

// After writing to the stack, set the Interupt flag to 1
// to prevent other interrupts
SetFlag(I, 1);

addr_abs = 0xFFFA;
uint16_t lo = read(addr_abs + 0);
uint16_t hi = read(addr_abs + 1);
Expand Down Expand Up @@ -894,7 +900,6 @@ uint8_t olc6502::BRK()
{
pc++;

SetFlag(I, 1);
write(0x0100 + stkp, (pc >> 8) & 0x00FF);
stkp--;
write(0x0100 + stkp, pc & 0x00FF);
Expand All @@ -905,6 +910,10 @@ uint8_t olc6502::BRK()
stkp--;
SetFlag(B, 0);

// After writing to the stack, set the Interupt flag to 1
// to prevent other interrupts
SetFlag(I, 1);

pc = (uint16_t)read(0xFFFE) | ((uint16_t)read(0xFFFF) << 8);
return 0;
}
Expand Down
17 changes: 13 additions & 4 deletions Part #5 - PPU Foregrounds/olc6502.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -68,7 +68,7 @@

Author
~~~~~~
David Barr, aka javidx9, �OneLoneCoder 2019
David Barr, aka javidx9, �OneLoneCoder 2019
*/

#include "olc6502.h"
Expand Down Expand Up @@ -208,10 +208,13 @@ void olc6502::irq()
// Then Push the status register to the stack
SetFlag(B, 0);
SetFlag(U, 1);
SetFlag(I, 1);
write(0x0100 + stkp, status);
stkp--;

// After writing to the stack, set the Interupt flag to 1
// to prevent other interrupts
SetFlag(I, 1);

// Read new program counter location from fixed address
addr_abs = 0xFFFE;
uint16_t lo = read(addr_abs + 0);
Expand All @@ -236,10 +239,13 @@ void olc6502::nmi()

SetFlag(B, 0);
SetFlag(U, 1);
SetFlag(I, 1);
write(0x0100 + stkp, status);
stkp--;

// After writing to the stack, set the Interupt flag to 1
// to prevent other interrupts
SetFlag(I, 1);

addr_abs = 0xFFFA;
uint16_t lo = read(addr_abs + 0);
uint16_t hi = read(addr_abs + 1);
Expand Down Expand Up @@ -894,7 +900,6 @@ uint8_t olc6502::BRK()
{
pc++;

SetFlag(I, 1);
write(0x0100 + stkp, (pc >> 8) & 0x00FF);
stkp--;
write(0x0100 + stkp, pc & 0x00FF);
Expand All @@ -905,6 +910,10 @@ uint8_t olc6502::BRK()
stkp--;
SetFlag(B, 0);

// After writing to the stack, set the Interupt flag to 1
// to prevent other interrupts
SetFlag(I, 1);

pc = (uint16_t)read(0xFFFE) | ((uint16_t)read(0xFFFF) << 8);
return 0;
}
Expand Down
17 changes: 13 additions & 4 deletions Part #7 - Mappers & Basic Sounds/olc6502.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -68,7 +68,7 @@

Author
~~~~~~
David Barr, aka javidx9, �OneLoneCoder 2019
David Barr, aka javidx9, �OneLoneCoder 2019
*/

#include "olc6502.h"
Expand Down Expand Up @@ -208,10 +208,13 @@ void olc6502::irq()
// Then Push the status register to the stack
SetFlag(B, 0);
SetFlag(U, 1);
SetFlag(I, 1);
write(0x0100 + stkp, status);
stkp--;

// After writing to the stack, set the Interupt flag to 1
// to prevent other interrupts
SetFlag(I, 1);

// Read new program counter location from fixed address
addr_abs = 0xFFFE;
uint16_t lo = read(addr_abs + 0);
Expand All @@ -236,10 +239,13 @@ void olc6502::nmi()

SetFlag(B, 0);
SetFlag(U, 1);
SetFlag(I, 1);
write(0x0100 + stkp, status);
stkp--;

// After writing to the stack, set the Interupt flag to 1
// to prevent other interrupts
SetFlag(I, 1);

addr_abs = 0xFFFA;
uint16_t lo = read(addr_abs + 0);
uint16_t hi = read(addr_abs + 1);
Expand Down Expand Up @@ -894,7 +900,6 @@ uint8_t olc6502::BRK()
{
pc++;

SetFlag(I, 1);
write(0x0100 + stkp, (pc >> 8) & 0x00FF);
stkp--;
write(0x0100 + stkp, pc & 0x00FF);
Expand All @@ -905,6 +910,10 @@ uint8_t olc6502::BRK()
stkp--;
SetFlag(B, 0);

// After writing to the stack, set the Interupt flag to 1
// to prevent other interrupts
SetFlag(I, 1);

pc = (uint16_t)read(0xFFFE) | ((uint16_t)read(0xFFFF) << 8);
return 0;
}
Expand Down
15 changes: 12 additions & 3 deletions Part#2 - CPU/olc6502.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -208,10 +208,13 @@ void olc6502::irq()
// Then Push the status register to the stack
SetFlag(B, 0);
SetFlag(U, 1);
SetFlag(I, 1);
write(0x0100 + stkp, status);
stkp--;

// After writing to the stack, set the Interupt flag to 1
// to prevent other interrupts
SetFlag(I, 1);

// Read new program counter location from fixed address
addr_abs = 0xFFFE;
uint16_t lo = read(addr_abs + 0);
Expand All @@ -236,10 +239,13 @@ void olc6502::nmi()

SetFlag(B, 0);
SetFlag(U, 1);
SetFlag(I, 1);
write(0x0100 + stkp, status);
stkp--;

// After writing to the stack, set the Interupt flag to 1
// to prevent other interrupts
SetFlag(I, 1);

addr_abs = 0xFFFA;
uint16_t lo = read(addr_abs + 0);
uint16_t hi = read(addr_abs + 1);
Expand Down Expand Up @@ -894,7 +900,6 @@ uint8_t olc6502::BRK()
{
pc++;

SetFlag(I, 1);
write(0x0100 + stkp, (pc >> 8) & 0x00FF);
stkp--;
write(0x0100 + stkp, pc & 0x00FF);
Expand All @@ -905,6 +910,10 @@ uint8_t olc6502::BRK()
stkp--;
SetFlag(B, 0);

// After writing to the stack, set the Interupt flag to 1
// to prevent other interrupts
SetFlag(I, 1);

pc = (uint16_t)read(0xFFFE) | ((uint16_t)read(0xFFFF) << 8);
return 0;
}
Expand Down