Miscellaneous routines
[Core]


Sector checking

u32 octant (int x, int y)
 Get the octant that (x, y) is in.
u32 octant_rot (int x0, int y0)
 Get the rotated octant that (x, y) is in.

Random numbers

int sqran (int seed)
INLINE int qran (void)
 Quick (and very dirty) pseudo-random number generator.
INLINE int qran_range (int min, int max)
 Ranged random number.
#define QRAN_SHIFT   15
#define QRAN_MASK   ((1<<QRAN_SHIFT)-1)
#define QRAN_MAX   QRAN_MASK

Inline assembly

#define ASM_CMT(str)   asm volatile("@# " str)
 Assembly comment.
#define ASM_BREAK()   asm volatile("\tmov\t\tr11, r11")
 No$gba breakpoint.
#define ASM_NOP()   asm volatile("\tnop")
 No-op; wait a bit.

Defines

#define STR(x)   #x
#define XSTR(x)   STR(x)
 Create text string from a literal.

Define Documentation

#define STR (  )     #x


Function Documentation

u32 octant ( int  x,
int  y 
)

Get the octant that (x, y) is in.

This function divides the circle in 8 parts. The angle starts at the y=0 line and then moves in the direction of the x=0 line. On the screen, this would be like starting at the 3 o'clock position and moving clockwise

u32 octant_rot ( int  x0,
int  y0 
)

Get the rotated octant that (x, y) is in.

Like octant() but with a twist. The 0-octant starts 22.5 earlier so that 3 o'clock falls in the middle of octant 0, instead of at its start. This can be useful for 8 directional pointing.

INLINE int qran ( void   ) 

Quick (and very dirty) pseudo-random number generator.

Returns:
random in range [0,8000h>

INLINE int qran_range ( int  min,
int  max 
)

Ranged random number.

Returns:
random in range [min, max>
Note:
(max-min) must be lower than 8000h


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