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Remove redundant inc_cycles()

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inc_cycles() was called in every case of the
CPU pattern matching. Since we return the number
of cycles of each instructions, we can increment
only afterwards.
This commit is contained in:
Fabien Freling 2016-02-17 23:14:33 +01:00
parent 1b7c60e94d
commit 27efc19125
1 changed files with 4 additions and 26 deletions
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30
src/cpu.ml
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@ -154,20 +154,17 @@ let run cpu (mem: Memory.map) =
| '\x7E' -> let inst = sprintf "LD \tA, (HL)" in
let hl = merge_bytes cpu.reg.l cpu.reg.h in
cpu.reg.a <- Memory.get mem hl;
inc_cycles cpu 8;
inst, 8
| '\x36' -> let n = read_pc_byte cpu mem in
let inst = sprintf "LD \t(HL) 0x%02X" n in
let hl = merge_bytes cpu.reg.l cpu.reg.h in
Memory.set mem hl (char_of_int n);
inc_cycles cpu 12;
inst, 12
(* CPU control *)
| '\x00' -> let inst = sprintf "NOP" in
inc_cycles cpu 4;
inst, 4
@ -178,26 +175,21 @@ let run cpu (mem: Memory.map) =
if cpu.flag.z = false then
begin
inc_pc cpu (s - 2); (* we read 2 bytes from PC, opcode and n *)
inc_cycles cpu 12;
inst, 12
end else begin
inc_cycles cpu 8;
inst, 8
end
| '\xC9' -> let inst = sprintf "RET" in
cpu.reg.pc <- pop_stack cpu mem;
inc_cycles cpu 16;
inst, 16
| '\xC0' -> let inst = sprintf "RET \tNZ" in
if cpu.flag.z = false then
begin
cpu.reg.pc <- pop_stack cpu mem;
inc_cycles cpu 20;
inst, 20
end else begin
inc_cycles cpu 8;
inst, 8
end
@ -205,7 +197,6 @@ let run cpu (mem: Memory.map) =
| '\x03' -> let inst = sprintf "INC \tBC" in
inc_BC cpu;
inc_cycles cpu 8;
inst, 8
| '\x05' -> let inst = sprintf "DEC \tB" in
@ -214,18 +205,16 @@ let run cpu (mem: Memory.map) =
cpu.flag.n <- true;
cpu.flag.h <- dec < 0;
cpu.reg.b <- char_of_int @@ if dec >= 0 then dec else 0;
inc_cycles cpu 4;
inst, 4
| '\x06' -> let n = read_pc_byte cpu mem in
let inst = sprintf "LD \tB, 0x%02X" n in
cpu.reg.b <- char_of_int n;
inc_cycles cpu 8;
inst, 8
| '\x18' -> let n = read_pc_byte cpu mem in
let inst = sprintf "JP \t0x%02X" n in
inc_pc cpu (n - 1); inc_cycles cpu 12;
inc_pc cpu (n - 1);
inst, 12
| '\x21' -> let nn = read_pc_2bytes cpu mem in
@ -233,7 +222,6 @@ let run cpu (mem: Memory.map) =
let high, low = split_2B nn in
cpu.reg.h <- high;
cpu.reg.l <- low;
inc_cycles cpu 12;
inst, 12
| '\x22' -> let inst = sprintf "LDI \t(HL), A" in
@ -242,7 +230,6 @@ let run cpu (mem: Memory.map) =
let high, low = split_2B (hl + 1) in
cpu.reg.h <- high;
cpu.reg.l <- low;
inc_cycles cpu 8;
inst, 8
@ -250,10 +237,9 @@ let run cpu (mem: Memory.map) =
let inst = sprintf "JR \tZ, 0x%02X" n in
if cpu.flag.z = true then
begin
inc_pc cpu (n - 1); inc_cycles cpu 12;
inc_pc cpu (n - 1);
inst, 12
end else begin
inc_cycles cpu 8;
inst, 8
end
@ -264,60 +250,51 @@ let run cpu (mem: Memory.map) =
cpu.flag.n <- false;
cpu.flag.h <- v = 0b00001111;
Memory.set mem hl (char_of_int (v + 1));
inc_cycles cpu 12;
inst, 12
| '\x3E' -> let n = read_pc_byte cpu mem in
let inst = sprintf "LD \tA, 0x%02X" n in
cpu.reg.a <- char_of_int n;
inc_cycles cpu 8;
inst, 8
| '\xAF' -> let inst = sprintf "XOR \tA, A" in
let int_A = int_of_char cpu.reg.a in
cpu.reg.a <- char_of_int @@ int_A lxor int_A;
inc_cycles cpu 4;
inst, 4
| '\xC3' -> let addr = read_pc_2bytes cpu mem in
let inst = sprintf "JP \t0x%04X" addr in
cpu.reg.pc <- addr; inc_cycles cpu 16;
cpu.reg.pc <- addr;
inst, 16
| '\xE0' -> let n = read_pc_byte cpu mem in
let inst = sprintf "LDH \t(0xFF%02X), A" n in
Memory.set mem (0xFF00 + n) cpu.reg.a;
inc_cycles cpu 12;
inst, 12
| '\xEA' -> let addr = read_pc_2bytes cpu mem in
let inst = sprintf "LD \t(0X%04X), A" addr in
Memory.set mem addr cpu.reg.a;
inc_cycles cpu 16;
inst, 16
| '\xF0' -> let n = read_pc_byte cpu mem in
let inst = sprintf "LDH \tA, (0xFF%02X)" n in
cpu.reg.a <- Memory.get mem (0xFF00 + n);
inc_cycles cpu 12;
inst, 12
| '\xF3' -> let inst = sprintf "DI" in
(* fixme *)
inc_cycles cpu 4;
inst, 4
| '\xFE' -> let n = read_pc_byte cpu mem in
let inst = sprintf "CP \t0x%02X" n in
cmp_A cpu n;
inc_cycles cpu 8;
inst, 8
| '\xFB' -> let inst = sprintf "EI" in
(* enable interrupts, IME=1 *)
inc_cycles cpu 4;
inst, 4
| x -> eprintf "opcode 0x%02X\n" (int_of_char x);
@ -325,4 +302,5 @@ let run cpu (mem: Memory.map) =
failwith "Unimplemented opcode."
in
inc_cycles cpu cycles;
inst, cycles