fix: fixes instructions JSR, PHA, PHP, PLA, RST, RTI, RTS, TSX and TXS

Author: gutomaia

src/cpu.js

@@ -982,7 +982,7 @@ CPU.prototype = {
         // *******
 
         // Transfer stack pointer to index X:
-        this.REG_X = this.REG_SP - 0x0100;
+        this.REG_X = this.REG_SP & 0xff;
         this.F_SIGN = (this.REG_SP >> 7) & 1;
         this.F_ZERO = this.REG_X;
         break;
@@ -1004,8 +1004,7 @@ CPU.prototype = {
         // *******
 
         // Transfer index X to stack pointer:
-        this.REG_SP = this.REG_X + 0x0100;
-        this.stackWrap();
+        this.REG_SP = this.REG_X & 0xff;
         break;
       }
       case 55: {
@@ -1294,19 +1293,16 @@ CPU.prototype = {
   },
 
   push: function (value) {
-    this.nes.mmap.write(this.REG_SP, value);
+    this.nes.mmap.write(this.REG_SP | 0x100, value);
     this.REG_SP--;
-    this.REG_SP = 0x0100 | (this.REG_SP & 0xff);
-  },
-
-  stackWrap: function () {
-    this.REG_SP = 0x0100 | (this.REG_SP & 0xff);
+    // this.REG_SP = 0x0100 | (this.REG_SP & 0xff);
+    this.REG_SP = this.REG_SP & 0xff;
   },
 
   pull: function () {
     this.REG_SP++;
-    this.REG_SP = 0x0100 | (this.REG_SP & 0xff);
-    return this.nes.mmap.load(this.REG_SP);
+    this.REG_SP = this.REG_SP & 0xff;
+    return this.nes.mmap.load(0x100 | this.REG_SP);
   },
 
   pageCrossed: function (addr1, addr2) {

test/cpu.spec.js

@@ -850,7 +850,6 @@ describe("CPU", function () {
     });
 
     it("tsx", function(done) {
-        this.skip("TODO");
         cpu_set_register("SP", 0xff);
         cpu_pc(0x100);
         memory_set(0x100, 0xba);
@@ -862,7 +861,6 @@ describe("CPU", function () {
     });
 
     it("txs", function(done) {
-        this.skip("TODO");
         cpu_set_register("X", 0xff);
         cpu_pc(0x100);
         memory_set(0x100, 0x9a);
@@ -874,7 +872,6 @@ describe("CPU", function () {
     });
 
     it("pha", function(done) {
-        this.skip();
         cpu_set_register("A", 0xff);
         cpu_pc(0x100);
         memory_set(0x100, 0x48);
@@ -886,7 +883,6 @@ describe("CPU", function () {
     });
 
     it("php", function(done) {
-        this.skip("TODO:");
         cpu_set_register("P", 0xff);
         cpu_pc(0x100);
         memory_set(0x100, 0x8);
@@ -898,7 +894,6 @@ describe("CPU", function () {
     });
 
     it("pla", function(done) {
-        this.skip();
         cpu_pc(0x100);
         cpu_push_byte(0xff);
         memory_set(0x100, 0x68);
@@ -921,7 +916,6 @@ describe("CPU", function () {
     });
 
     it("pla z flag unset", function(done) {
-        this.skip();
         cpu_push_byte(0x1);
         cpu_pc(0x100);
         memory_set(0x100, 0x68);
@@ -933,7 +927,6 @@ describe("CPU", function () {
     });
 
     it("pla n flag set", function(done) {
-        this.skip();
         cpu_push_byte(0x81);
         cpu_pc(0x100);
         memory_set(0x100, 0x68);
@@ -3478,7 +3471,6 @@ describe("CPU", function () {
     });
 
     it("jsr", function(done) {
-        this.skip("TODO: check SP register");
         cpu_pc(0x100);
         memory_set(0x100, 0x20);
         memory_set(0x101, 0xff);
@@ -3493,7 +3485,6 @@ describe("CPU", function () {
     });
 
     it("jsr stack pointer", function(done) {
-        this.skip("TODO:");
         cpu_pc(0x100);
         memory_set(0x100, 0x20);
         memory_set(0x101, 0x84);
@@ -3539,7 +3530,6 @@ describe("CPU", function () {
     });
 
     it("rts", function(done) {
-        this.skip("TODO");
         cpu_pc(0x100);
         cpu_push_word(0x102);
         memory_set(0x100, 0x60);
@@ -3864,7 +3854,6 @@ describe("CPU", function () {
     });
 
     it("rti", function(done) {
-        this.skip("TODO");
         cpu_pc(0x100);
         cpu_push_word(0x102);
         cpu_push_byte(0x3);