1. Changing data tables and pointers (which you can't do with the standard hooks)
2. Replacing code without introducing unnecessary jumps (might be useful in core loops, like the draw distance check which is run once for every object every frame)

source\example.s


ovr_02013DDC: @ change starting character
.byte 0x01 @ Luigi

ovr_020FF176_ov_02: @ change character speeds
.hword 0x1000 @ Yoshi

ovr_02128D18_ov_51: @ change Ice Block vtable pointers
.word 0x020B382C @ onGroundPounded: change to BrickBlock:onGroundPounded
.word new_IceBlockExploded @ onHitByExplosion: change to new_IceBlockExploded

.align @ return to 4 byte alignment for below instructions

new_IceBlockExploded: @ do nothing and return because lazy example
bx r14

• Can only be used in ".s" files


• You can have several "ovr_" blocks in a single file, but each block must be self-contained (each block is compiled separately for its specified code address, to ensure correct relative branch opcodes are generated). The only exception is the ability to reference labels with a "new_" prefix, as shown in the above example.


• Do not use "ldr rX, =0xXXXXXXXX" instructions in overwrites unless you really know what you are doing (they can take up 8 bytes, but not always).


• Overwrites are now compiled and inserted after standard hooks.


• Everything in the \source folder (not including subfolders) is compiled and inserted into unused ROM space, specifically the old "arena" (this is default NSMBe behaviour). Overwrites are therefore also compiled and duplicated here. This shouldn't be a problem, as it is just unused code, but if you have large overwrites and don't want to waste arena space, you can wrap your overwrites inside a special block like so:
  
  
  /*overwrite
  
  ovr_02013DDC: @ change starting character
  .byte 0x01 @ Luigi
  
  ovr_020FF176_ov_02: @ change character speeds
  .hword 0x1000 @ Yoshi
  
  overwrite*/
  
  The hook compiler treats this as a multi-line comment block (so it is not compiled), but the overwrite parser will still compile and insert it. Note however that you cannot nest comment blocks, so you would not be able to use any multi-line comments inside the "/*overwrite" block.
  

Ice Blocks: breakability when attacked

To make them breakable: here
To change which characters can break them, see "Brick Blocks / Black Brick Blocks: who can break" in the first post

• Fixed crash bug when trying to overwrite an address in ARM9.
• No longer spams multiple console windows, output from all compiles appear in the same console window.
• No need for separate \overwrites folder and files anymore. Use "ovr_" just like you would standard hooks, including in the same file as other hooks (but still only in ".s" files).
• Can now overwrite single bytes or any number of bytes (no longer needs to be in 4-byte multiples)
• Now recognise /* multi-line comment blocks */.

Posted by Hiccup

The reason the ice block breaking works with the shards may be because you technically can break them if you hack Giant Mario into the level and walk into one.

Player: move speed and acceleration

See here (including ceiling hang and slippery slide)

Despite what many game guides say, all characters have the exact same acceleration and deceleration (and no, Luigi does not have a faster top speed than Mario).
Also, thanks to Skelux's "Increase Acceleration" additional patch for the memory address re ground acceleration.


Player: carry speed

Regular and heavy objects: here


Player: swim speed

See here


Player: jump power

See here (including back flip, side flip and long jump)

Posted by StarPants

I saw there was something going on in the registers but couldn't analyse it any further. I'm glad you got it.

unrelatedly: If anyone's doing a kaizo they can try to nop at 0x020BF330. I tried in first person and it felt pretty much like a motorbike without breaks. Never rode one irl though.

ldr r2, [r0, 0x8] // r2 = 4 bytes at address (r0 + 0x8) = charID (0:M, 1:L, 2:W, 3:Y)
ldr r0, =0x020FF170 // r0 = 0x020FF170
and r2, r2, 0xFF // r2 = r2 bitwise AND 0xFF (seems unnecessary?)
mov r2, r2, lsl 0x1 // r2 *= r2 (left shift 1 bit is effectively x2) = charID x2
ldrh r2, [r0, r2] // r2 = 2 bytes at address (0x020FF170 + charID x2)

• Bug fix: overwrite parser no longer stops looking for "ovr_" blocks once it finds a non ".s" file.
• New feature: can now refer to "new_" labels inside overwrite blocks - this allows you to insert pointers or branches to new code (where address is unknown prior to compile). Please note that overwrites are now parsed and inserted AFTER standard hooks as a result.