Yoshi's Cookie/RAM map

The following article is a RAM map for Yoshi's Cookie.

RAM Map

Address Size    Description
------- ----    -----------
0000       2    mode jump address (LSB)
00A0       1    speed (01=low, 02=med, 03=hi)
0200     768    playfield matrix
0300      32    playfield dropping row
0320      32    playfield dropping column
0340       4    playfield dropping corner
03D9       1    mode
03E2       1    cursorY * 2
03E3       1    cursorX * 2
048E       1    00=playing, 02=paused
040B       1    round (01--0A)
040C       1    stage (01--0A)
0490       1    buttons pressed (bits)
0492       1    title screen option (01=1P, 02=VS)
04A0       1    00=playing, FF=demo
04A8       1    1P menu option (01=round, 02=speed, 03=music type)
05E4       1    continue (01=yes, 02=no)

Playfield

The playfield is an 8×8 matrix stored in 768 bytes starting at address $0200.  Each element is represented by 4 bytes, each of which corresponds to a pattern table entry.  In other words, each cookie or Mario character is a 2×2 meta-tile; the upper 2 and the lower 2 bytes are adjacent in memory and the upper and lower pairs are separated by 16 bytes.  Each element can be one of 8 possible values:

empty
00 00
00 00

green koopa troopa shell
08 09
0A 0B

heart / super mushroom
10 11
20 21

flower / boo buddy
12 13
22 23

diamond / goomba
14 15
24 25

check / jumpin' piranha plant
16 17
26 27

circle / bloober
18 19
28 29

yoshi
1A 1B
2A 2B

The dropping row is stored in 32 bytes starting at address $0300. Each element is in the same 2×2 meta-tile format as the playfield matrix.

The dropping column is stored in 32 bytes starting at address $0320. However, unlike the playfield matrix and the dropping row, the 4 bytes of each element are stored sequentially.

The dropping corner element is stored as 4 bytes starting at address $0340. Like the dropping column, its 4 bytes are stored sequentially.

Mode

A single byte at $03D9 indicates the current game mode:

01 = title / continue
02 = playing / demo
03 = rotating rows / columns
04 = round X
05 = 1P mario enter animation
06 = game over
07 = clearing rows / columns
08 = shuffling rows / columns
09 = AxB points
0D = clearing rows / columns
0F = stage clear
12 = 1P menu
13 = 1P menu animation
14 = stage start push start
15 = paused
19 = adding rows / columns
1C = demo
36 = interstitial
37 = easy ending
38 = hard ending

A jump address is injected into $0000 when the mode changes (see ROM Map).