bsnes/processor/hg51b/instructions.cpp

357 lines
8.0 KiB
C++

#ifdef PROCESSOR_HG51B_HPP
auto HG51B::push() -> void {
stack[7] = stack[6];
stack[6] = stack[5];
stack[5] = stack[4];
stack[4] = stack[3];
stack[3] = stack[2];
stack[2] = stack[1];
stack[1] = stack[0];
stack[0] = regs.pc;
}
auto HG51B::pull() -> void {
regs.pc = stack[0];
stack[0] = stack[1];
stack[1] = stack[2];
stack[2] = stack[3];
stack[3] = stack[4];
stack[4] = stack[5];
stack[5] = stack[6];
stack[6] = stack[7];
stack[7] = 0x0000;
}
//Shift-A: math opcodes can shift A register prior to ALU operation
auto HG51B::sa() -> uint {
switch(opcode & 0x0300) { default:
case 0x0000: return regs.a << 0;
case 0x0100: return regs.a << 1;
case 0x0200: return regs.a << 8;
case 0x0300: return regs.a << 16;
}
}
//Register-or-Immediate: most opcodes can load from a register or immediate
auto HG51B::ri() -> uint {
if(opcode & 0x0400) return opcode & 0xff;
return reg_read(opcode & 0xff);
}
//New-PC: determine jump target address; opcode.d9 = long jump flag (1 = yes)
auto HG51B::np() -> uint {
if(opcode & 0x0200) return (regs.p << 8) | (opcode & 0xff);
return (regs.pc & 0xffff00) | (opcode & 0xff);
}
auto HG51B::instruction() -> void {
if((opcode & 0xffff) == 0x0000) {
//0000 0000 0000 0000
//nop
}
else if((opcode & 0xdd00) == 0x0800) {
//00.0 10.0 .... ....
//jump i
if(opcode & 0x2000) push();
regs.pc = np();
}
else if((opcode & 0xdd00) == 0x0c00) {
//00.0 11.0 .... ....
//jumpeq i
if(regs.z) {
if(opcode & 0x2000) push();
regs.pc = np();
}
}
else if((opcode & 0xdd00) == 0x1000) {
//00.1 00.0 .... ....
//jumpge i
if(regs.c) {
if(opcode & 0x2000) push();
regs.pc = np();
}
}
else if((opcode & 0xdd00) == 0x1400) {
//00.1 01.0 .... ....
//jumpmi i
if(regs.n) {
if(opcode & 0x2000) push();
regs.pc = np();
}
}
else if((opcode & 0xffff) == 0x1c00) {
//0001 1100 0000 0000
//loop?
}
else if((opcode & 0xfffe) == 0x2500) {
//0010 0101 0000 000.
//skiplt/skipge
if(regs.c == (opcode & 1)) regs.pc++;
}
else if((opcode & 0xfffe) == 0x2600) {
//0010 0110 0000 000.
//skipne/skipeq
if(regs.z == (opcode & 1)) regs.pc++;
}
else if((opcode & 0xfffe) == 0x2700) {
//0010 0111 0000 000.
//skipmi/skippl
if(regs.n == (opcode & 1)) regs.pc++;
}
else if((opcode & 0xffff) == 0x3c00) {
//0011 1100 0000 0000
//ret
pull();
}
else if((opcode & 0xffff) == 0x4000) {
//0100 0000 0000 0000
//rdbus
regs.busdata = bus_read(regs.busaddr++);
}
else if((opcode & 0xf800) == 0x4800) {
//0100 1... .... ....
//cmpr a<<n,ri
int result = ri() - sa();
regs.n = result & 0x800000;
regs.z = (uint24)result == 0;
regs.c = result >= 0;
}
else if((opcode & 0xf800) == 0x5000) {
//0101 0... .... ....
//cmp a<<n,ri
int result = sa() - ri();
regs.n = result & 0x800000;
regs.z = (uint24)result == 0;
regs.c = result >= 0;
}
else if((opcode & 0xfb00) == 0x5900) {
//0101 1.01 .... ....
//sxb
regs.a = (int8)ri();
}
else if((opcode & 0xfb00) == 0x5a00) {
//0101 1.10 .... ....
//sxw
regs.a = (int16)ri();
}
else if((opcode & 0xfb00) == 0x6000) {
//0110 0.00 .... ....
//ld a,ri
regs.a = ri();
}
else if((opcode & 0xfb00) == 0x6100) {
//0110 0.01 .... ....
//ld ?,ri
}
else if((opcode & 0xfb00) == 0x6300) {
//0110 0.11 .... ....
//ld p,ri
regs.p = ri();
}
else if((opcode & 0xfb00) == 0x6800) {
//0110 1.00 .... ....
//rdraml
uint24 target = ri() + (opcode & 0x0400 ? regs.ramaddr : (uint24)0);
if(target < 0xc00) regs.ramdata = (regs.ramdata & 0xffff00) | (dataRAM[target] << 0);
}
else if((opcode & 0xfb00) == 0x6900) {
//0110 1.01 .... ....
//rdramh
uint24 target = ri() + (opcode & 0x0400 ? regs.ramaddr : (uint24)0);
if(target < 0xc00) regs.ramdata = (regs.ramdata & 0xff00ff) | (dataRAM[target] << 8);
}
else if((opcode & 0xfb00) == 0x6a00) {
//0110 1.10 .... ....
//rdramb
uint24 target = ri() + (opcode & 0x0400 ? regs.ramaddr : (uint24)0);
if(target < 0xc00) regs.ramdata = (regs.ramdata & 0x00ffff) | (dataRAM[target] << 16);
}
else if((opcode & 0xffff) == 0x7000) {
//0111 0000 0000 0000
//rdrom
regs.romdata = dataROM[regs.a & 0x3ff];
}
else if((opcode & 0xff00) == 0x7c00) {
//0111 1100 .... ....
//ld pl,i
regs.p = (regs.p & 0xff00) | ((opcode & 0xff) << 0);
}
else if((opcode & 0xff00) == 0x7d00) {
//0111 1101 .... ....
//ld ph,i
regs.p = (regs.p & 0x00ff) | ((opcode & 0xff) << 8);
}
else if((opcode & 0xf800) == 0x8000) {
//1000 0... .... ....
//add a<<n,ri
int result = sa() + ri();
regs.a = result;
regs.n = regs.a & 0x800000;
regs.z = regs.a == 0;
regs.c = result > 0xffffff;
}
else if((opcode & 0xf800) == 0x8800) {
//1000 1... .... ....
//subr a<<n,ri
int result = ri() - sa();
regs.a = result;
regs.n = regs.a & 0x800000;
regs.z = regs.a == 0;
regs.c = result >= 0;
}
else if((opcode & 0xf800) == 0x9000) {
//1001 0... .... ....
//sub a<<n,ri
int result = sa() - ri();
regs.a = result;
regs.n = regs.a & 0x800000;
regs.z = regs.a == 0;
regs.c = result >= 0;
}
else if((opcode & 0xfb00) == 0x9800) {
//1001 1.00 .... ....
//mul a,ri
int64 x = (int24)regs.a;
int64 y = (int24)ri();
x *= y;
regs.accl = x >> 0ull;
regs.acch = x >> 24ull;
regs.n = regs.acch & 0x800000;
regs.z = x == 0;
}
else if((opcode & 0xf800) == 0xa800) {
//1010 1... .... ....
//xor a<<n,ri
regs.a = sa() ^ ri();
regs.n = regs.a & 0x800000;
regs.z = regs.a == 0;
}
else if((opcode & 0xf800) == 0xb000) {
//1011 0... .... ....
//and a<<n,ri
regs.a = sa() & ri();
regs.n = regs.a & 0x800000;
regs.z = regs.a == 0;
}
else if((opcode & 0xf800) == 0xb800) {
//1011 1... .... ....
//or a<<n,ri
regs.a = sa() | ri();
regs.n = regs.a & 0x800000;
regs.z = regs.a == 0;
}
else if((opcode & 0xfb00) == 0xc000) {
//1100 0.00 .... ....
//shr a,ri
regs.a = regs.a >> ri();
regs.n = regs.a & 0x800000;
regs.z = regs.a == 0;
}
else if((opcode & 0xfb00) == 0xc800) {
//1100 1.00 .... ....
//asr a,ri
regs.a = (int24)regs.a >> ri();
regs.n = regs.a & 0x800000;
regs.z = regs.a == 0;
}
else if((opcode & 0xfb00) == 0xd000) {
//1101 0.00 .... ....
//ror a,ri
uint24 length = ri();
regs.a = (regs.a >> length) | (regs.a << (24 - length));
regs.n = regs.a & 0x800000;
regs.z = regs.a == 0;
}
else if((opcode & 0xfb00) == 0xd800) {
//1101 1.00 .... ....
//shl a,ri
regs.a = regs.a << ri();
regs.n = regs.a & 0x800000;
regs.z = regs.a == 0;
}
else if((opcode & 0xff00) == 0xe000) {
//1110 0000 .... ....
//st r,a
reg_write(opcode & 0xff, regs.a);
}
else if((opcode & 0xfb00) == 0xe800) {
//1110 1.00 .... ....
//wrraml
uint24 target = ri() + (opcode & 0x0400 ? regs.ramaddr : (uint24)0);
if(target < 0xc00) dataRAM[target] = regs.ramdata >> 0;
}
else if((opcode & 0xfb00) == 0xe900) {
//1110 1.01 .... ....
//wrramh
uint24 target = ri() + (opcode & 0x0400 ? regs.ramaddr : (uint24)0);
if(target < 0xc00) dataRAM[target] = regs.ramdata >> 8;
}
else if((opcode & 0xfb00) == 0xea00) {
//1110 1.10 .... ....
//wrramb
uint24 target = ri() + (opcode & 0x0400 ? regs.ramaddr : (uint24)0);
if(target < 0xc00) dataRAM[target] = regs.ramdata >> 16;
}
else if((opcode & 0xff00) == 0xf000) {
//1111 0000 .... ....
//swap a,r
uint24 source = reg_read(opcode & 0xff);
uint24 target = regs.a;
regs.a = source;
reg_write(opcode & 0xff, target);
}
else if((opcode & 0xffff) == 0xfc00) {
//1111 1100 0000 0000
//halt
regs.halt = true;
}
else {
print("Hitachi DSP: unknown opcode @ ", hex(regs.pc - 1, 4L), " = ", hex(opcode, 4L), "\n");
regs.halt = true;
}
}
#endif