Here is a list of all documented files with brief descriptions:

16c550.h [code]
asm.h [code]	Assembly helper
bmp.h [code]	Software bitmap engine
config.h [code]	Basic SGDK library configuration file
dma.h [code]	DMA support
everdrive.h [code]	Everdrive support
fat16.h [code]	FAT16 file system support
font.h [code]	SGDK system Font
gamejolt.h [code]	GameJolt Game API implementation for MegaWiFi
genesis.h [code]
joy.h [code]	General controller support
jsmn.h [code]
json.h [code]	JSON implementation, based on jsmn by Serge Zaitsev
kdebug.h [code]	Gens KMod debug methods
libres.h [code]
lsd.h [code]
map.h [code]	MAP (large background map) management unit
mapper.h [code]	Mapper / bank switch methods
maths.h [code]	Mathematical methods
maths3D.h [code]	3D math engine
megawifi.h [code]	MegaWiFi API implementation
memory.h [code]	Memory handling methods
mw-msg.h [code]	MegaWiFi command message definitions
pal.h [code]	Palette support (herited from vdp_pal.h unit)
psg.h [code]	PSG support
smp_null.h [code]
smp_null_pcm.h [code]
sound.h [code]	Audio / Sound stuff
sprite_eng.h [code]	Sprite engine
sram.h [code]	SRAM (Static RAM used for save backup) support
string.h [code]	String manipulations
sys.h [code]	Entry point unit / Interrupt callback / System
tab_cnv.h [code]
tab_vol.h [code]
task.h [code]	User task support
task_cst.h [code]	User task constantes definition
timer.h [code]	Timer support
tools.h [code]	Misc tools methods
types.h [code]	Types definition
vdp.h [code]	VDP main
vdp_bg.h [code]	VDP background plane support
vdp_dma.h [code]	VDP DMA support
vdp_pal.h [code]
vdp_spr.h [code]	VDP Sprite support
vdp_tile.h [code]	VDP General Tile / Tilemap operations
vram.h [code]	SGDK VRAM (Video Memory) management unit
xgm.h [code]	XGM sound driver
ym2612.h [code]	YM2612 support
z80_ctrl.h [code]	Z80 control