Type casting: double to char: multiple questions

Consider this code:

#include <stdio.h>int main(void) {    /* TEST 1 */    double d = 128;    char ch = (char)d;    printf("%d\n", ch);    /* TEST 2 */    printf("%d\n", (char)128.0);    /* TEST 3 */    char ch1 = (char)128.0;    printf("%d\n", ch1);    return 0;}

Results:

        gcc*  clang*  cl*TEST 1  -128  -128    -128TEST 2  127   0       -128TEST 3  127   -2      -128* latest version

Questions:

1. Why the results differ between tests (excluding cl)?
2. Why the results differ between compilers (excluding TEST 1)?
3. In case of UB/IB, where is the UB/IB exactly? What the standard says?
4. [Extra question] Why clang shows so different behavior? Where these 0 and -2 come from?