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dyncom: Add a helper function for addition with a carry

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This commit is contained in:
Lioncash 2015-01-12 00:01:46 -05:00
parent eacc2a501b
commit 9c2c89b7e1
3 changed files with 26 additions and 12 deletions
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21
src/core/arm/dyncom/arm_dyncom_interpreter.cpp
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@ -4003,16 +4003,13 @@ unsigned InterpreterMainLoop(ARMul_State* state) {
}
ADC_INST:
{
adc_inst *inst_cream = (adc_inst *)inst_base->component;
if ((inst_base->cond == 0xe) || CondPassed(cpu, inst_base->cond)) {
u32 left = RN;
u32 right = SHIFTER_OPERAND;
if (inst_base->cond == 0xE || CondPassed(cpu, inst_base->cond)) {
adc_inst* const inst_cream = (adc_inst*)inst_base->component;
u64 unsigned_sum = (left + right + cpu->CFlag);
s64 signed_sum = (s64)(s32)left + (s64)(s32)right + (s64)cpu->CFlag;
u32 result = (unsigned_sum & 0xFFFFFFFF);
bool carry;
bool overflow;
RD = AddWithCarry(RN, SHIFTER_OPERAND, cpu->CFlag, &carry, &overflow);
RD = result;
if (inst_cream->S && (inst_cream->Rd == 15)) {
if (CurrentModeHasSPSR) {
cpu->Cpsr = cpu->Spsr_copy;
@ -4020,10 +4017,10 @@ unsigned InterpreterMainLoop(ARMul_State* state) {
LOAD_NZCVT;
}
} else if (inst_cream->S) {
UPDATE_NFLAG(result);
UPDATE_ZFLAG(result);
UPDATE_CFLAG_CARRY_FROM_ADD(left, right, cpu->CFlag);
cpu->VFlag = ((s64)(s32)result != signed_sum);
UPDATE_NFLAG(RD);
UPDATE_ZFLAG(RD);
cpu->CFlag = carry;
cpu->VFlag = overflow;
}
if (inst_cream->Rd == 15) {
INC_PC(sizeof(adc_inst));

16
src/core/arm/interpreter/armsupp.cpp
View file

@ -418,6 +418,22 @@ ARMul_NegZero (ARMul_State * state, ARMword result)
}
}
// Add with carry, indicates if a carry-out or signed overflow occurred.
u32 AddWithCarry(u32 left, u32 right, u32 carry_in, bool* carry_out_occurred, bool* overflow_occurred)
{
u64 unsigned_sum = (u64)left + (u64)right + (u64)carry_in;
s64 signed_sum = (s64)(s32)left + (s64)(s32)right + (s64)carry_in;
u64 result = (unsigned_sum & 0xFFFFFFFF);
if (carry_out_occurred)
*carry_out_occurred = (result != unsigned_sum);
if (overflow_occurred)
*overflow_occurred = ((s64)(s32)result != signed_sum);
return (u32)result;
}
// Compute whether an addition of A and B, giving RESULT, overflowed.
bool AddOverflow(ARMword a, ARMword b, ARMword result)
{

1
src/core/arm/skyeye_common/armdefs.h
View file

@ -795,6 +795,7 @@ extern void ARMul_FixSPSR(ARMul_State*, ARMword, ARMword);
extern void ARMul_ConsolePrint(ARMul_State*, const char*, ...);
extern void ARMul_SelectProcessor(ARMul_State*, unsigned);
extern u32 AddWithCarry(u32, u32, u32, bool*, bool*);
extern bool ARMul_AddOverflowQ(ARMword, ARMword);
extern u8 ARMul_SignedSaturatedAdd8(u8, u8);