diff options
Diffstat (limited to 'gc.h')
-rw-r--r-- | gc.h | 8 |
1 files changed, 8 insertions, 0 deletions
@@ -81,6 +81,14 @@ int ruby_get_stack_grow_direction(volatile VALUE *addr); # define STACK_UPPER(x, a, b) (stack_growup_p(x) ? (a) : (b)) #endif +/* + STACK_GROW_DIR_DETECTION is used with STACK_DIR_UPPER. + + On most normal systems, stacks grow from high address to lower address. In + this case, STACK_DIR_UPPER(a, b) will return (b), but on exotic systems where + the stack grows UP (from low address to high address), it will return (a). +*/ + #if STACK_GROW_DIRECTION #define STACK_GROW_DIR_DETECTION #define STACK_DIR_UPPER(a,b) STACK_UPPER(0, (a), (b)) |