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Added decimal mode (untested): http://www.6502.org/tutorials/decimal_mode.html

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git-svn-id: svn://svn.cc65.org/cc65/trunk@4327 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
uz 2009-10-04 18:52:10 +00:00
parent ca5ada12ba
commit 8b7c9fdc4f
1 changed files with 160 additions and 127 deletions
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55
src/sim65/cpucore.c
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@ -221,11 +221,28 @@ static char BreakMsg[1024];
/* ADC */
#define ADC(v) \
if (GET_DF ()) { \
Warning ("Decimal mode not available"); \
} else { \
do { \
unsigned old = Regs.AC; \
unsigned rhs = (v & 0xFF); \
if (GET_DF ()) { \
unsigned lo; \
int res; \
lo = (old & 0x0F) + (rhs & 0x0F) + GET_CF (); \
if (lo >= 0x0A) { \
lo = ((lo + 0x06) & 0x0F) + 0x10; \
} \
Regs.AC = (old & 0xF0) + (rhs & 0xF0) + lo; \
res = (signed char)(old & 0xF0) + \
(signed char)(rhs & 0xF0) + \
(signed char)lo; \
TEST_ZF (old + rhs + GET_CF ()); \
TEST_SF (Regs.AC); \
if (Regs.AC >= 0xA0) { \
Regs.AC += 0x60; \
} \
TEST_CF (Regs.AC); \
SET_OF ((res < -128) || (res > 127)); \
} else { \
Regs.AC += rhs + GET_CF (); \
TEST_ZF (Regs.AC); \
TEST_SF (Regs.AC); \
@ -233,7 +250,8 @@ static char BreakMsg[1024];
SET_OF (!((old ^ rhs) & 0x80) && \
((old ^ Regs.AC) & 0x80)); \
Regs.AC &= 0xFF; \
}
} \
} while (0)
/* branches */
#define BRANCH(cond) \
@ -254,12 +272,12 @@ static char BreakMsg[1024];
/* compares */
#define CMP(v1,v2) \
{ \
do { \
unsigned Result = v1 - v2; \
TEST_ZF (Result & 0xFF); \
TEST_SF (Result); \
SET_CF (Result <= 0xFF); \
}
} while (0)
/* ROL */
@ -284,19 +302,34 @@ static char BreakMsg[1024];
/* SBC */
#define SBC(v) \
if (GET_DF ()) { \
Warning ("Decimal mode not available"); \
} else { \
do { \
unsigned old = Regs.AC; \
unsigned rhs = (v & 0xFF); \
if (GET_DF ()) { \
unsigned lo; \
int res; \
lo = (old & 0x0F) - (rhs & 0x0F) + GET_CF () - 1; \
if (lo & 0x80) { \
lo = ((lo - 0x06) & 0x0F) - 0x10; \
} \
Regs.AC = (old & 0xF0) - (rhs & 0xF0) + lo; \
if (Regs.AC & 0x80) { \
Regs.AC -= 0x60; \
} \
res = Regs.AC - rhs + (!GET_CF ()); \
TEST_ZF (res); \
TEST_SF (res); \
SET_CF (res <= 0xFF); \
SET_OF (((old^rhs) & (old^res) & 0x80)); \
} else { \
Regs.AC -= rhs - (!GET_CF ()); \
TEST_ZF (Regs.AC); \
TEST_SF (Regs.AC); \
SET_CF (Regs.AC <= 0xFF); \
SET_OF (((old^rhs) & (old^Regs.AC) & 0x80)); \
Regs.AC &= 0xFF; \
}
} \
} while (0)
/*****************************************************************************/