#New trouble game rules warp xx movie#

This gives us 20 E3 8F, which is impossible because 0ењЋ3 ends on x3 and 0x8F ends on xF. Now the second example, let's do the same thing except we jump to $8FE3. For this to be possible, all bits in the first byte need to occur in the second byte, which is the case here! This is exactly what the showcased run did, but unfortunately without setting $0100 (req. It doesn't really matter if we start at $F5 or $F6, but the important part to notice is how the 0x20 and 0xB8 are made with the same input. Since two bytes are not enough, we have to use the second block of inputs. None of the bytes require opposite directional inputs, so that's good. As you can see, the JMP's are already impossible as they end on xC (= requiring an Up+Down press). There are three jump instructions: JSR(0x20), JMP(0x4C), indirect JMP(0ењ†C). This makes building bytes that end on x3,x7,xB,xC,xD,ењЋ, or xF impossible, limiting our choice of opcodes.ДЄs a first example, let's construct a jump to $B85A. That's barely enough to do anything, and it gets even worse: Up+Down and Left+Right presses are cancelled out. Then, $F5 is P1 new input, $F6 is P2 new input, $F7 is P1 input, $F8 is P2 input. In particular $17 is P1 input, $18 is P1 new input. In addition to currently pressed input bytes, we also have newly pressed input bytes (those are always a subset of the currently pressed bits). In order from most to least significant bit the buttons go: A B Select Start Up Down Left Right. We have two controllers with 8 buttons each.

#New trouble game rules warp xx movie#

What makes this whole movie possible in the first place are the bytes of controller input stored in RAM. So we're now at the start of RAM filled mostly with 00's we can safely execute. They change into 'default mode' where IRQ finally doesn't jump into different banks. The Stack Pointer points to memory values $01xx, so after another BRK we will overwrite $0100 (= NMI mode) and $0101 (= IRQ mode). Here, X happens to be 0x00, so the Stack Pointer (innitially 0xFF and in normal execution 0xC0-0xFF) is suddenly 0x00 and after a return it's 0x02. Instruction 0x9A is TXS, Transfer X to Stack Pointer. Until at some point the very unlikely scenario happens where a leftover byte from an indirect $9Axx jump is executed. A lot of crazy things happen (such as interrupts interrupting each other), and they keep getting more out of control because of IRQ trying to execute on wrong banks. So it jumps into the middle of a wrong routine. Unfortunately for the game, NMI did not yet finish and the banks are still switched. IRQ expects the NMI to have finished long ago and jumps to $A826.

Eventually the NMI is interrupted by IRQ, a different interrupt which is set to run at scanline 192 or 193 (= late in the frame). Important to notice here is how NMI switches to different banks at the start, and would switch them back at the end. As soon as it begins we delay the execution by changing the input each loop. By continuously changing inputs we can delay the game because it keeps waiting until two consecutive inputs match.ДЇor convenience, the game has the controller reading routine inside the NMI, which is the interrupt that runs at the start of each frame. This is what ais523 meant when talking about creating precise amounts of lag. So of course we can mash buttons really fast. Now this is TASVideos: When human skills are just not enough.