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808x: Fix the flags at the end of the ADC and SBB instructions, fixes #4103.

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OBattler
2024-02-03 04:33:42 +01:00
parent ff5ea614ee
commit 91494bab97
1 changed files with 18 additions and 4 deletions
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22
src/cpu/808x.c
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@@ -1223,34 +1223,48 @@ static void
add(int bits) add(int bits)
{ {
int size_mask = (1 << bits) - 1; int size_mask = (1 << bits) - 1;
int special_case = 0;
uint32_t temp_src = cpu_src;
if ((cpu_alu_op == 2) && !(cpu_src & size_mask) && (cpu_state.flags & C_FLAG))
special_case = 1;
cpu_data = cpu_dest + cpu_src; cpu_data = cpu_dest + cpu_src;
if ((cpu_alu_op == 2) && (cpu_state.flags & C_FLAG))
cpu_src--;
set_apzs(bits); set_apzs(bits);
set_of_add(bits); set_of_add(bits);
/* Anything - FF with carry on is basically anything + 0x100: value stays /* Anything - FF with carry on is basically anything + 0x100: value stays
unchanged but carry goes on. */ unchanged but carry goes on. */
if ((cpu_alu_op == 2) && !(cpu_src & size_mask) && (cpu_state.flags & C_FLAG)) if (special_case)
cpu_state.flags |= C_FLAG; cpu_state.flags |= C_FLAG;
else else
set_cf((cpu_src & size_mask) > (cpu_data & size_mask)); set_cf((temp_src & size_mask) > (cpu_data & size_mask));
} }
static void static void
sub(int bits) sub(int bits)
{ {
int size_mask = (1 << bits) - 1; int size_mask = (1 << bits) - 1;
int special_case = 0;
uint32_t temp_src = cpu_src;
if ((cpu_alu_op == 3) && !(cpu_src & size_mask) && (cpu_state.flags & C_FLAG))
special_case = 1;
cpu_data = cpu_dest - cpu_src; cpu_data = cpu_dest - cpu_src;
if ((cpu_alu_op == 3) && (cpu_state.flags & C_FLAG))
cpu_src--;
set_apzs(bits); set_apzs(bits);
set_of_sub(bits); set_of_sub(bits);
/* Anything - FF with carry on is basically anything - 0x100: value stays /* Anything - FF with carry on is basically anything - 0x100: value stays
unchanged but carry goes on. */ unchanged but carry goes on. */
if ((cpu_alu_op == 3) && !(cpu_src & size_mask) && (cpu_state.flags & C_FLAG)) if (special_case)
cpu_state.flags |= C_FLAG; cpu_state.flags |= C_FLAG;
else else
set_cf((cpu_src & size_mask) > (cpu_dest & size_mask)); set_cf((temp_src & size_mask) > (cpu_dest & size_mask));
} }
static void static void