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Implemented RLC and RRC instructions #28

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merged 4 commits into from
Mar 10, 2024
Merged

Implemented RLC and RRC instructions #28

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96834e7
Implemented RRC/RLC
ddpigeon Feb 8, 2024
88a9891
minor bug in naming
ddpigeon Feb 8, 2024
c885d4c
Fixed bugs involving zero flag
ddpigeon Mar 9, 2024
40b6298
Merge branch 'dev' into prabhanjan
Vignaraj-pai Mar 10, 2024
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6 changes: 5 additions & 1 deletion include/CPU.h
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Original file line number Diff line number Diff line change
Expand Up @@ -70,6 +70,10 @@ class CPU {
void PFX_SLA_HL(); // Shift Left Arithmetically for HL
void PFX_RES_R8();
void PFX_RES_HL();
void PFX_RLC_R8();
void PFX_RLC_HL();
void PFX_RRC_R8();
void PFX_RRC_HL();
void PFX_SRA_R8(); //prefix instruction for arithmetic right shift
void PFX_SRA_HL(); //prefix instruction for arithmetic right shift with HL
void PFX_SRL_R8(); //prefix instruction for logical right shift
Expand Down Expand Up @@ -122,4 +126,4 @@ class CPU {
uint8_t pfx_rs_family_index;
};

#endif
#endif
77 changes: 77 additions & 0 deletions src/cpu/ins_prefix.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,17 @@ void CPU::PFX()
}
}

if (pfx_rs_family_index == 0b000){
//RLC
if(pfx_register_index == 0b110){
PFX_RLC_HL();
cycles = (3+1);
}
else{
PFX_RLC_R8();
cycles = (1+1);
}
}

if (pfx_bit_index == 0b101){ // SRA
if(pfx_register_index == 0b110){
Expand All @@ -42,6 +53,18 @@ void CPU::PFX()
}
}

if (pfx_rs_family_index == 0b001){
//RRC
if(pfx_register_index == 0b110){
PFX_RRC_HL();
cycles = (3+1);
}
else{
PFX_RRC_R8();
cycles = (1+1);
}
}

if (pfx_bit_index == 0b111){ // SRL
if(pfx_register_index == 0b110){
PFX_SRL_HL();
Expand Down Expand Up @@ -378,3 +401,57 @@ void CPU::PFX_SRL_R8()
set_flag(Flags::zero, 1);
}
}

void CPU::PFX_RLC_R8()
{
uint8_t bit_7 = (*pfx_register_ptr) >> 7;
*pfx_register_ptr <<= 1;
*pfx_register_ptr |= bit_7;

set_flag(Flags::neg, 0);
set_flag(Flags::half_carry, 0);
set_flag(Flags::zero, *pfx_register_ptr == 0);
set_flag(Flags::carry, bit_7);
}

void CPU::PFX_RLC_HL()
{
operand = read8(HL.full);
operand_addr = HL.full;
uint8_t bit_7 = (operand) >> 7;
operand <<= 1;
operand |= bit_7;
write8(operand_addr, operand);

set_flag(Flags::neg, 0);
set_flag(Flags::half_carry, 0);
set_flag(Flags::zero, operand == 0);
set_flag(Flags::carry, bit_7);
}

void CPU::PFX_RRC_R8()
{
uint8_t bit_0 = (*pfx_register_ptr) & 1;
*pfx_register_ptr >>= 1;
*pfx_register_ptr |= (bit_0 << 7);

set_flag(Flags::neg, 0);
set_flag(Flags::half_carry, 0);
set_flag(Flags::zero, *pfx_register_ptr == 0);
set_flag(Flags::carry, bit_0);
}

void CPU::PFX_RRC_HL()
{
operand = read8(HL.full);
operand_addr = HL.full;
uint8_t bit_0 = (operand) & 1;
operand >>= 1;
operand |= (bit_0 << 7);
write8(operand_addr, operand);

set_flag(Flags::neg, 0);
set_flag(Flags::half_carry, 0);
set_flag(Flags::zero, operand == 0);
set_flag(Flags::carry, bit_0);
}