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use less variables
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@gwenhael-le-moine
gwenhael-le-moine committed Sep 11, 2024
1 parent 780de5f commit 901ec9d
Showing 1 changed file with 31 additions and 43 deletions.
74 changes: 31 additions & 43 deletions src/emu_emulate.c
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Original file line number Diff line number Diff line change
Expand Up @@ -206,10 +206,7 @@ static inline void add_address( word_20* dat, int add )
{
*dat += add;

if ( *dat & ( word_20 )0xfff00000 )
saturn.CARRY = 1;
else
saturn.CARRY = 0;
saturn.CARRY = ( *dat & ( word_20 )0xfff00000 ) ? 1 : 0;

*dat &= 0xfffff;
}
Expand Down Expand Up @@ -257,8 +254,8 @@ static bool step_instruction_00e( void )
bool illegal_instruction = false;

int op2 = read_nibble( saturn.PC + 2 );
int op3 = read_nibble( saturn.PC + 3 );
switch ( op3 ) {

switch ( read_nibble( saturn.PC + 3 ) ) {
case 0: /* A=A&B */
saturn.PC += 4;
and_register( saturn.A, saturn.A, saturn.B, op2 );
Expand Down Expand Up @@ -334,8 +331,7 @@ static bool step_instruction_00( void )
{
bool illegal_instruction = false;

int op1 = read_nibble( saturn.PC + 1 );
switch ( op1 ) {
switch ( read_nibble( saturn.PC + 1 ) ) {
case 0: /* RTNSXM */
saturn.XM = 1;
saturn.PC = pop_return_addr();
Expand Down Expand Up @@ -449,8 +445,7 @@ static bool step_instruction_010( void )
{
bool illegal_instruction = false;

int op3 = read_nibble( saturn.PC + 2 );
switch ( op3 ) {
switch ( read_nibble( saturn.PC + 2 ) ) {
case 0: /* saturn.R0=A */
saturn.PC += 3;
copy_register( saturn.R0, saturn.A, W_FIELD );
Expand Down Expand Up @@ -508,8 +503,7 @@ static bool step_instruction_011( void )
{
bool illegal_instruction = false;

int op3 = read_nibble( saturn.PC + 2 );
switch ( op3 ) {
switch ( read_nibble( saturn.PC + 2 ) ) {
case 0: /* A=R0 */
saturn.PC += 3;
copy_register( saturn.A, saturn.R0, W_FIELD );
Expand Down Expand Up @@ -567,8 +561,7 @@ static bool step_instruction_012( void )
{
bool illegal_instruction = false;

int op3 = read_nibble( saturn.PC + 2 );
switch ( op3 ) {
switch ( read_nibble( saturn.PC + 2 ) ) {
case 0: /* AR0EX */
saturn.PC += 3;
exchange_register( saturn.A, saturn.R0, W_FIELD );
Expand Down Expand Up @@ -626,8 +619,7 @@ static bool step_instruction_013( void )
{
bool illegal_instruction = false;

int op3 = read_nibble( saturn.PC + 2 );
switch ( op3 ) {
switch ( read_nibble( saturn.PC + 2 ) ) {
case 0: /* D0=A */
saturn.PC += 3;
register_to_address( saturn.A, &saturn.D0, 0 );
Expand Down Expand Up @@ -833,10 +825,9 @@ static bool step_instruction_015( void )
static bool step_instruction_01( void )
{
bool illegal_instruction = false;
int op2 = read_nibble( saturn.PC + 1 );
int op3;

switch ( op2 ) {
switch ( read_nibble( saturn.PC + 1 ) ) {
case 0:
illegal_instruction = step_instruction_010();
break;
Expand Down Expand Up @@ -1011,10 +1002,7 @@ static bool step_instruction_08a( void )
{
bool illegal_instruction = false;

int op2 = read_nibble( saturn.PC + 2 );
int op3;

switch ( op2 ) {
switch ( read_nibble( saturn.PC + 2 ) ) {
case 0: /* ?A=B */
saturn.CARRY = is_equal_register( saturn.A, saturn.B, A_FIELD );
break;
Expand Down Expand Up @@ -1068,7 +1056,9 @@ static bool step_instruction_08a( void )
}
if ( saturn.CARRY ) {
saturn.PC += 3;
op3 = read_nibbles( saturn.PC, 2 );

int op3 = read_nibbles( saturn.PC, 2 );

if ( op3 ) {
if ( op3 & 0x80 )
op3 |= jumpmasks[ 2 ];
Expand Down Expand Up @@ -1179,10 +1169,9 @@ static bool step_instruction_080( void )
{
bool illegal_instruction = false;

int op3 = read_nibble( saturn.PC + 2 );
int op4;

switch ( op3 ) {
switch ( read_nibble( saturn.PC + 2 ) ) {
case 0: /* OUT=CS */
saturn.PC += 3;
copy_register( saturn.OUT, saturn.C, OUTS_FIELD );
Expand Down Expand Up @@ -1437,8 +1426,9 @@ static bool step_instruction_0818( void )
bool illegal_instruction = false;

int op3 = read_nibble( saturn.PC + 3 );
int op4 = read_nibble( saturn.PC + 4 );
int op5 = read_nibble( saturn.PC + 5 );

int op4 = read_nibble( saturn.PC + 4 );
if ( op4 < 8 ) { /* PLUS */
switch ( op4 & 3 ) {
case 0: /* A=A+CON */
Expand Down Expand Up @@ -1520,9 +1510,8 @@ static bool step_instruction_081a0( void )
{
bool illegal_instruction = false;
int op3 = read_nibble( saturn.PC + 3 );
int op5 = read_nibble( saturn.PC + 5 );

switch ( op5 ) {
switch ( read_nibble( saturn.PC + 5 ) ) {
case 0: /* saturn.R0=A */
saturn.PC += 6;
copy_register( saturn.R0, saturn.A, op3 );
Expand Down Expand Up @@ -1580,9 +1569,8 @@ static bool step_instruction_081a1( void )
{
bool illegal_instruction = false;
int op3 = read_nibble( saturn.PC + 3 );
int op5 = read_nibble( saturn.PC + 5 );

switch ( op5 ) {
switch ( read_nibble( saturn.PC + 5 ) ) {
case 0: /* A=R0 */
saturn.PC += 6;
copy_register( saturn.A, saturn.R0, op3 );
Expand Down Expand Up @@ -1640,9 +1628,8 @@ static bool step_instruction_081a2( void )
{
bool illegal_instruction = false;
int op3 = read_nibble( saturn.PC + 3 );
int op5 = read_nibble( saturn.PC + 5 );

switch ( op5 ) {
switch ( read_nibble( saturn.PC + 5 ) ) {
case 0: /* AR0EX */
saturn.PC += 6;
exchange_register( saturn.A, saturn.R0, op3 );
Expand Down Expand Up @@ -1700,8 +1687,7 @@ static bool step_instruction_081a( void )
{
bool illegal_instruction = false;

int op4 = read_nibble( saturn.PC + 4 );
switch ( op4 ) {
switch ( read_nibble( saturn.PC + 4 ) ) {
case 0:
illegal_instruction = step_instruction_081a0();
break;
Expand All @@ -1721,9 +1707,8 @@ static bool step_instruction_081a( void )
static bool step_instruction_081b( void )
{
bool illegal_instruction = false;
int op3 = read_nibble( saturn.PC + 3 );

switch ( op3 ) {
switch ( read_nibble( saturn.PC + 3 ) ) {
case 2: /* PC=A */
saturn.PC = dat_to_addr( saturn.A );
break;
Expand Down Expand Up @@ -1758,9 +1743,8 @@ static bool step_instruction_081b( void )
static bool step_instruction_081( void )
{
bool illegal_instruction = false;
int op2 = read_nibble( saturn.PC + 2 );

switch ( op2 ) {
switch ( read_nibble( saturn.PC + 2 ) ) {
case 0: /* ASLC */
saturn.PC += 3;
shift_left_circ_register( saturn.A, W_FIELD );
Expand Down Expand Up @@ -1832,10 +1816,7 @@ static bool step_instruction_08b( void )
{
bool illegal_instruction = false;

int op2 = read_nibble( saturn.PC + 2 );
int op3;

switch ( op2 ) {
switch ( read_nibble( saturn.PC + 2 ) ) {
case 0: /* ?A>B */
saturn.CARRY = is_greater_register( saturn.A, saturn.B, A_FIELD );
break;
Expand Down Expand Up @@ -1889,7 +1870,9 @@ static bool step_instruction_08b( void )
}
if ( saturn.CARRY ) {
saturn.PC += 3;
op3 = read_nibbles( saturn.PC, 2 );

int op3 = read_nibbles( saturn.PC, 2 );

if ( op3 ) {
if ( op3 & 0x80 )
op3 |= jumpmasks[ 2 ];
Expand Down Expand Up @@ -2039,6 +2022,7 @@ static bool step_instruction_09( void )
bool illegal_instruction = false;
int op1 = read_nibble( saturn.PC + 1 );
int op2 = read_nibble( saturn.PC + 2 );

if ( op1 < 8 ) {
switch ( op2 ) {
case 0: /* ?A=B */
Expand Down Expand Up @@ -2149,7 +2133,9 @@ static bool step_instruction_09( void )
}
if ( saturn.CARRY ) {
saturn.PC += 3;

int op3 = read_nibbles( saturn.PC, 2 );

if ( op3 ) {
if ( op3 & 0x80 )
op3 |= jumpmasks[ 2 ];
Expand All @@ -2169,6 +2155,7 @@ static bool step_instruction_0a( void )
bool illegal_instruction = false;
int op1 = read_nibble( saturn.PC + 1 );
int op2 = read_nibble( saturn.PC + 2 );

if ( op1 < 8 ) {
switch ( op2 ) {
case 0: /* A=A+B */
Expand Down Expand Up @@ -2318,6 +2305,7 @@ static bool step_instruction_0b( void )
bool illegal_instruction = false;
int op1 = read_nibble( saturn.PC + 1 );
int op2 = read_nibble( saturn.PC + 2 );

if ( op1 < 8 ) {
switch ( op2 ) {
case 0: /* A=A-B */
Expand Down

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