X-Git-Url: http://git.scottworley.com/planeteer/blobdiff_plain/bc4a3744c612277ded9e74e3463934f127b46041..db81510d35a720dc85793c0684a9c13a5ae38237:/planeteer.go

diff --git a/planeteer.go b/planeteer.go
index d81713e..7c5b2e7 100644
--- a/planeteer.go
+++ b/planeteer.go
@@ -170,16 +170,18 @@ func ReadData() (data planet_data) {
  * independent -- some combinations are illegal and not used.  They are
  * handled as three dimensions rather than one for simplicity.  Placing
  * these dimensions first causes the unused cells in the table to be
- * grouped together in large blocks.  This keeps them from polluting
- * cache lines, and if they are large enough, allows the memory manager
- * to swap out entire pages.
+ * grouped together in large blocks.  This keeps the unused cells from
+ * polluting cache lines, and if the spans of unused cells are large
+ * enough, allows the memory manager to swap out entire pages.
  *
  * If the table gets too big to fit in RAM:
  *    * Combine the Edens, Cloaks, and UnusedCargo dimensions.  Of the
  *      24 combinations, only 15 are legal: a 38% savings.
- *    * Reduce the size of the Fuel dimension to 3.  We only ever look
- *      backwards 2 units, so just rotate the logical values through
- *      the same 3 physical addresses.  This is good for an 82% savings.
+ *    * Reduce the size of the Fuel dimension to 3.  Explicit iteration
+ *      only ever needs to look backwards 2 units, so the logical values
+ *      can rotate through the same 3 physical addresses.  This would be
+ *      good for an 82% savings.  Note that explicit iteration went away
+ *      in 0372f045.
  *    * Reduce the size of the Edens dimension from 3 to 2, for the
  *      same reasons as Fuel above.  33% savings.
  *    * Buy more ram.  (Just sayin'.  It's cheaper than you think.)
@@ -246,7 +248,8 @@ func StateTableSize(dims []int) int {
 }
 
 type State struct {
-	value, from int32
+	value int32
+	from  PhysicalIndex
 }
 
 const (
@@ -257,7 +260,9 @@ const (
 	VALUE_RUBISH
 )
 
-func EncodeIndex(dims, addr []int) int32 {
+type PhysicalIndex int32
+
+func EncodeIndex(dims, addr []int) PhysicalIndex {
 	index := addr[0]
 	if addr[0] > dims[0] {
 		panic(0)
@@ -268,16 +273,17 @@ func EncodeIndex(dims, addr []int) int32 {
 		}
 		index = index*dims[i] + addr[i]
 	}
-	return int32(index)
+	return PhysicalIndex(index)
 }
 
-func DecodeIndex(dims []int, index int32) []int {
+func DecodeIndex(dims []int, index PhysicalIndex) []int {
+	scratch := int(index)
 	addr := make([]int, NumDimensions)
 	for i := NumDimensions - 1; i > 0; i-- {
-		addr[i] = int(index) % dims[i]
-		index /= int32(dims[i])
+		addr[i] = scratch % dims[i]
+		scratch /= dims[i]
 	}
-	addr[0] = int(index)
+	addr[0] = scratch
 	return addr
 }
 
@@ -551,8 +557,8 @@ func FinalState(dims []int) []int {
 	return addr
 }
 
-func FindBestState(data planet_data, dims []int, table []State, addr []int) int32 {
-	max_index := int32(-1)
+func FindBestState(data planet_data, dims []int, table []State, addr []int) PhysicalIndex {
+	max_index := PhysicalIndex(-1)
 	max_value := 0.0
 	max_fuel := 1
 	if *fuel == 0 {
@@ -591,7 +597,7 @@ func Commas(n int32) (s string) {
 	return
 }
 
-func FighterAndShieldCost(data planet_data, dims []int, table []State, best int32) {
+func FighterAndShieldCost(data planet_data, dims []int, table []State, best PhysicalIndex) {
 	if *drones == 0 && *batteries == 0 {
 		return
 	}
@@ -612,7 +618,7 @@ func FighterAndShieldCost(data planet_data, dims []int, table []State, best int3
 	}
 }
 
-func EndEdensCost(data planet_data, dims []int, table []State, best int32) {
+func EndEdensCost(data planet_data, dims []int, table []State, best PhysicalIndex) {
 	if *end_edens == 0 {
 		return
 	}
@@ -628,7 +634,7 @@ func EndEdensCost(data planet_data, dims []int, table []State, best int32) {
 	}
 }
 
-func VisitCost(data planet_data, dims []int, table []State, best int32) {
+func VisitCost(data planet_data, dims []int, table []State, best PhysicalIndex) {
 	if dims[Visit] == 1 {
 		return
 	}
@@ -643,7 +649,7 @@ func VisitCost(data planet_data, dims []int, table []State, best int32) {
 	}
 }
 
-func EndLocationCost(data planet_data, dims []int, table []State, best int32) {
+func EndLocationCost(data planet_data, dims []int, table []State, best PhysicalIndex) {
 	if len(end()) == 0 {
 		return
 	}
@@ -658,7 +664,7 @@ func EndLocationCost(data planet_data, dims []int, table []State, best int32) {
 	*end_string = save_end_string
 }
 
-func DescribePath(data planet_data, dims []int, table []State, start int32) (description []string) {
+func DescribePath(data planet_data, dims []int, table []State, start PhysicalIndex) (description []string) {
 	for index := start; table[index].from > FROM_ROOT; index = table[index].from {
 		if table[index].from == FROM_UNINITIALIZED {
 			panic(index)