void test2()
{
unsigned int a = 9;
printf("a:\n");
printBits(a);
setBitAt(&a, 10, 1);
printf("a after setBitAt(&a,10,1):\n");
printBits(a);
setBitAt(&a, 20, 1);
printf("a after setBitAt(&a,20,1):\n");
printBits(a);
setBitAt(&a, 0, 0);
printf("a after setBitAt(&a,0,0):\n");
printBits(a);
setBitAt(&a, 3, 0);
printf("a after setBitAt(&a,3,0):\n");
printBits(a);
}
void calcAddress(int* r, int isPreIndex, char* arg3, char* arg4, char* arg5) {
/* POST-INDEXING
* It is of the following two forms
* [Rn], #expression
* [Rn], {+/-}Rm{, <shift>}
*
* PRE-INDEXING
* It is of the following two forms
* Note the bracket close in the second one
* [Rn, #expression]
* [Rn, {+/-}Rm{, <shift>}]
*/
if(arg3[0] == '#') {
//#expression] form (']' depends on indexing)
if(isPreIndex) isInClear(']', arg3, MAX_ARG_SIZE);
int offset = strToInt(arg3, MAX_ARG_SIZE);
//offset must fit in 12bits as signed number
if(offset > 0x7ff || offset < ((int)(0xfffff800))) {
printf("ERROR: Cannot fit offset value \"%d\" to 12 bits in ldr\n", offset);
exit(EXIT_FAILURE);
}
//If it does continue
int isNeg = getBitAt(&offset, 31);
//Set U Flag, add or subtract offset
setBitAt(r, 23, isNeg == 0);
if(isNeg) {
offset = -(offset);
}
//Set the offset
setBitsAt(r, 0, &offset, 0, 11);
} else {
//{+/-}Rm{, <shift>}] ']' depends on indexing form
//SET IFLAG as offset is a shifted register
//NOTE OPPOSITE CASE IN SINGLE DATA TRANSFER
if(getBitAt(r, 26)) setBitAt(r, 25, 1);
//Is the bracket closing? If yes, then there is no shift
//Rm] or Rm, <shift>] for pre-index
//Rm, <shift>
//Clear any closing brackets from Rm] in pre-indexing
if(isPreIndex) isInClear(']', arg3, MAX_ARG_SIZE);
//Check positive or negative and get Rm value
int Rm;
if(arg3[0] == '-') {
//Set U Flag to subtract offset
setBitAt(r, 23, 0); //subtract
//Omit '-' when parsing
Rm = strToInt(arg3 + 1, MAX_ARG_SIZE - 1);
} else {
//By default the UFLAG is set to add
Rm = strToInt(arg3, MAX_ARG_SIZE);
}
//Set Rm
setBitsAt(r, 0, &Rm, 0, 4);
if(arg4[0] != '\0') {
/*THERE IS SHIFTING
* It can be 1 of the following
* <shift> <register>]
* <shift> <#expression>]
* ']' depend on indexing type
*/
//Get and set the shift code
int shiftCode = getShiftCode(arg4);
setBitsAt(r, 5, &shiftCode, 0, 2);
//get rid of closing brackets if pre-indexing
if(isPreIndex) isInClear(']', arg5, MAX_ARG_SIZE);
//Check the second argument to shift
if(arg5[0] == '#') {
//<#expression> form
int shift_amount = strToInt(arg5, MAX_ARG_SIZE);
//Shift amount must fit into 5 bits
if(shift_amount > 0x1f) {
printf("ERROR: Too large immediate shift value: %d\n", shift_amount);
exit(EXIT_FAILURE);
}
//Set the shift amount
setBitsAt(r, 7, &shift_amount, 0, 5);
} else {
//<register> form
//Set register shift flag
setBitAt(r, 4, 1);
//Get and set Rs
int Rs = strToInt(arg5, MAX_ARG_SIZE);
setBitsAt(r, 8, &Rs, 0, 4);
}
}
} //endof if(arg3[0] == '#') else
}
