Ton document
http://www.amiga-ng.org/resources/OptimizeForAltivec.pdf
est particuliérement impressionnant : je le sauvegarde dans un coin
Voici un exemple simple de prog Altivec pour faire du YUV vers RGB (=conversion d'une image video)
à recompiler/tester sur Amiga PPC
https://github.com/fungos/seed/blob/master/contrib/oggplay/ppc/oggplay_yuv2rgb_altivec.cLes structures en parametres sont définies ainsi
struct _OggPlayYUVChannels
structure holds pointers to y, u, v channels
unsigned char * ptru U channel.
unsigned char * ptrv V channel.
unsigned char * ptry Y channel.
int uv_height the height of the U/V plane
int uv_width the width of the U/V plane
int y_height the height of the Y plane
int y_width the width of the Y plane
struct _OggPlayRGBChannels
structure holds pointers to RGB packets
unsigned char * ptro the RGB stream in the requested packaging format
int rgb_height height of the RGB frame
int rgb_width width of the RGB frame