Объяснить строку кода - C (СИ) (75160)

#include <stdio.h>
#include <stdint.h>
#include <limits.h>
 
#define is_negative(a) ( ( (a) >> ( sizeof(a) * CHAR_BIT - 1 ) ) & 1 )
 
int main(void) {
    int8_t a8 = -1;
    int8_t b8 = 1;
    int16_t a16 = -1;
    int16_t b16 = 1;
    int32_t a32 = -1;
    int32_t b32 = 1;
    
    printf("a8 (%hhd) is %s\n", a8, ( is_negative(a8) ) ? "negative" : "positive or zero");
    printf("b8 (%hhd) is %s\n", b8, ( is_negative(b8) ) ? "negative" : "positive or zero");
    printf("a16 (%hd) is %s\n", a16, ( is_negative(a16) ) ? "negative" : "positive or zero");
    printf("b16 (%hd) is %s\n", b16, ( is_negative(b16) ) ? "negative" : "positive or zero");
    printf("a32 (%d) is %s\n", a32, ( is_negative(a32) ) ? "negative" : "positive or zero");
    printf("b32 (%d) is %s\n", b32, ( is_negative(b32) ) ? "negative" : "positive or zero");
    
    return 0;
}