yar

cpu/set_arithmetic.go

@@ -1,5 +1,8 @@
 package cpu
 
+// The implementation of the add with carry.
+//
+// This will change flags in the Core it's run in.
 func (c *Core) adc_impl(middle byte) {
 	if c.Features.DecimalModeImplemented && c.Flags&FLAG_DECIMAL > 0 {
 		c.adc_impl_decimal(middle)
@@ -39,6 +42,9 @@ func (c *Core) adc_impl(middle byte) {
 	}
 }
 
+// The implementation of the add with carry using BCD.
+//
+// This will change flags in the Core it's run in.
 func (c *Core) adc_impl_decimal(middle byte) {
 	var u1 = uint16(c.A)
 	var u2 = uint16(middle)
@@ -92,6 +98,9 @@ func (c *Core) adc_impl_decimal(middle byte) {
 	}
 }
 
+// The implementation of the subtract with borrow.
+//
+// This will change flags in the Core it's run in.
 func (c *Core) sbc_impl(middle byte) {
 	if c.Features.DecimalModeImplemented && c.Flags&FLAG_DECIMAL > 0 {
 		c.sbc_impl_decimal(middle)
@@ -133,6 +142,9 @@ func (c *Core) sbc_impl(middle byte) {
 	}
 }
 
+// The implementation of the subtract with borrow using BCD.
+//
+// This will change flags in the Core it's run in.
 func (c *Core) sbc_impl_decimal(middle byte) {
 	var u1 = uint16(c.A)
 	var u2 = uint16(middle)

cpu/set_branch.go

@@ -1,5 +1,9 @@
 package cpu
 
+// Takes a unsigned 8 bit integer and mangles it into a signed 8 bit integer.
+//
+// The result is converted into a unsigned short to add to the program counter
+// by the caller.
 func branchVal(i uint8) (o uint16) {
 	m := int8(i & 0x7F)
 	if i&0b10000000 > 0 {

cpu/set_comparetest.go

@@ -1,5 +1,9 @@
 package cpu
 
+// This is the implementation of what the `CMP`, `CPX`, and `CPY` instructions
+// do.
+//
+// This will change the flags in the Core it's run in.
 func (c *Core) cmp_impl(what, with byte) {
 	if what == with {
 		c.Flags = c.Flags & ^FLAG_NEGATIVE
@@ -16,6 +20,9 @@ func (c *Core) cmp_impl(what, with byte) {
 	}
 }
 
+// This is the implementation of what the `BIT` instruction does.
+//
+// This will change the flags in the Core it's run in.
 func (c *Core) bit_impl(with byte) {
 	var r = c.A & with
 

cpu/set_incdec.go

@@ -1,5 +1,9 @@
 package cpu
 
+// The implementation of the increment instructions.
+//
+// This will change the flags of the of the Core it's run in, and will change the
+// value at the pointer passed into it.
 func (c *Core) inc_impl(where *byte) {
 	*where++
 
@@ -18,6 +22,10 @@ func (c *Core) inc_impl(where *byte) {
 	}
 }
 
+// The implementation of the decrement instructions.
+//
+// This will change the flags of the of the Core it's run in, and will change the
+// value at the pointer passed into it.
 func (c *Core) dec_impl(where *byte) {
 	*where--
 

cpu/set_load.go

@@ -1,5 +1,9 @@
 package cpu
 
+// This is the implementation of the load instructions.
+//
+// This will change the flags of the Core it's run in, and will change the value
+// at the pointer passed into it.
 func (c *Core) ld_impl(to *byte, store byte) {
 	*to = store
 

cpu/set_logic.go

@@ -1,5 +1,8 @@
 package cpu
 
+// This is the implementation of the AND instructions.
+//
+// This will change the flags of the Core it's run in.
 func (c *Core) and_impl(with byte) {
 	c.A = c.A & with
 
@@ -16,6 +19,9 @@ func (c *Core) and_impl(with byte) {
 	}
 }
 
+// This is the implementation of the ORA instructions.
+//
+// This will change the flags of the Core it's run in.
 func (c *Core) ora_impl(with byte) {
 	c.A = c.A | with
 
@@ -32,6 +38,9 @@ func (c *Core) ora_impl(with byte) {
 	}
 }
 
+// This is the implementation of the EOR instructions.
+//
+// This will change the flags of the Core it's run in.
 func (c *Core) eor_impl(with byte) {
 	c.A = c.A ^ with
 

cpu/set_shiftrot.go

@@ -1,5 +1,8 @@
 package cpu
 
+// This is the implementation of the ASL instructions.
+//
+// This will change the flags of the Core it's run in.
 func (c *Core) asl_impl(loc *byte) {
 	var shouldCarry = *loc & 0x80
 
@@ -24,6 +27,9 @@ func (c *Core) asl_impl(loc *byte) {
 	}
 }
 
+// This is the implementation of the LSR instructions.
+//
+// This will change the flags of the Core it's run in.
 func (c *Core) lsr_impl(loc *byte) {
 	var shouldCarry = *loc & 0x01
 
@@ -48,6 +54,9 @@ func (c *Core) lsr_impl(loc *byte) {
 	}
 }
 
+// This is the implementation of the ROL instructions.
+//
+// This will change the flags of the Core it's run in.
 func (c *Core) rol_impl(loc *byte) {
 	var futureCarry = *loc & 0b10000000
 
@@ -72,6 +81,9 @@ func (c *Core) rol_impl(loc *byte) {
 	}
 }
 
+// This is the implementation of the ROR instructions.
+//
+// This will change the flags of the Core it's run in.
 func (c *Core) ror_impl(loc *byte) {
 	var futureCarry = *loc & 0b00000001