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Iterate over pointers instead of copies.

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Modify addressable to become a pointer because Go's range does not
provide a pointer to the element but a copy of the element (urgh).

Go's range operator really can be considered broken.  In this case it
copies the addressable all the time which significantly slows things
down.  To boot, it isn't writing in the memory you think it is (it ends
up in the copy of memory).

Before the change:
$ go test -v -test.run Klaus
=== RUN TestKlausDormann6502
Running Klaus Dormann' 6502 functional tests. This may take some time...
Klaus Dormann's 6502 functional tests passed.
--- PASS: TestKlausDormann6502 (13.51s)
PASS
ok      github.com/ariejan/i6502        13.522s

After the change:
$ go test -v -test.run Klaus
=== RUN TestKlausDormann6502
Running Klaus Dormann' 6502 functional tests. This may take some time...
Klaus Dormann's 6502 functional tests passed.
--- PASS: TestKlausDormann6502 (4.87s)
PASS
ok      github.com/ariejan/i6502        4.877s
This commit is contained in:
Marco Peereboom 2015-04-08 16:56:35 -05:00
parent 21a7136dd6
commit 43f3d06988
1 changed files with 4 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
address_bus.go
View File

@ -11,7 +11,7 @@ address space of the Cpu to the relative memory addressing of
each component.
*/
type AddressBus struct {
addressables []addressable // Different components
addressables []*addressable // Different components
}
type addressable struct {
@ -26,7 +26,7 @@ func (a *addressable) String() string {
// Creates a new, empty 16-bit AddressBus
func NewAddressBus() (*AddressBus, error) {
return &AddressBus{addressables: make([]addressable, 0)}, nil
return &AddressBus{addressables: make([]*addressable, 0)}, nil
}
// Returns a string with details about the AddressBus and attached memory
@ -54,7 +54,7 @@ func (a *AddressBus) Attach(memory Memory, offset uint16) {
end := offset + memory.Size() - 1
addressable := addressable{memory: memory, start: start, end: end}
a.addressables = append(a.addressables, addressable)
a.addressables = append(a.addressables, &addressable)
}
/*
@ -112,7 +112,7 @@ func (a *AddressBus) Write16(address uint16, data uint16) {
func (a *AddressBus) addressableForAddress(address uint16) (*addressable, error) {
for _, addressable := range a.addressables {
if addressable.start <= address && addressable.end >= address {
return &addressable, nil
return addressable, nil
}
}