Add ROLL 2ROT words.

Author: Molorius

README.md

@@ -827,6 +827,7 @@ all can be in the future.
 
 # Standard Double extension words
 
+* `2ROT`
 * `2VALUE`
 * `DU<`
 

pkg/forth/builtin/03_double.f

@@ -94,3 +94,7 @@
     POSTPONE @
     POSTPONE ;
 ;
+
+: 2ROT
+    5 ROLL 5 ROLL
+;

pkg/forth/primitive.go

@@ -2094,6 +2094,76 @@ func PrimitiveSetup(vm *VirtualMachine) error {
 				},
 			},
 		},
+		{
+			name: "ROLL",
+			flag: Flag{
+				isPure: true,
+			},
+			goFunc: func(vm *VirtualMachine, entry *DictionaryEntry) error {
+				n, err := vm.Stack.PopNumber()
+				if err != nil {
+					return PopError(err, entry)
+				}
+				shifts := int(n)
+				values := make([]Cell, shifts)
+				for i := 0; i < int(n); i++ {
+					j := shifts - i - 1
+					cell, err := vm.Stack.Pop()
+					if err != nil {
+						return PopError(err, entry)
+					}
+					values[j] = cell
+				}
+				top, err := vm.Stack.Pop()
+				if err != nil {
+					return PopError(err, entry)
+				}
+				for _, c := range values {
+					err = vm.Stack.Push(c)
+					if err != nil {
+						return PushError(err, entry)
+					}
+				}
+				err = vm.Stack.Push(top)
+				if err != nil {
+					return PushError(err, entry)
+				}
+				return nil
+			},
+			ulpAsm: PrimitiveUlp{
+				Asm: []string{
+					"ld r0, r3, 0",
+					"add r2, r3, r0",
+					"ld r1, r2, 1",
+					"st r1, r3, 0",
+					"__roll_0:",
+					"add r2, r3, r0",
+					"ld r1, r2, 0",
+					"st r1, r2, 1",
+					"sub r0, r0, 1",
+					"jumpr __roll_0, -1, lt",
+					"add r3, r3, 1",
+				},
+				Next: TokenNextNormal,
+			},
+			ulpAsmSrt: PrimitiveUlpSrt{
+				Asm: []string{
+					"st r2, r3, -1",
+					"ld r0, r3, 0",
+					"add r2, r3, r0",
+					"ld r1, r2, 1",
+					"st r1, r3, 0",
+					"__roll_0:",
+					"add r2, r3, r0",
+					"ld r1, r2, 0",
+					"st r1, r2, 1",
+					"sub r0, r0, 1",
+					"jumpr __roll_0, -1, lt",
+					"ld r2, r3, -1",
+					"add r3, r3, 1",
+				},
+			},
+		},
 		{
 			name: "DROP",
 			flag: Flag{

pkg/forth/suite_test.go

@@ -1509,7 +1509,14 @@ func TestCoreExtensionSuite(t *testing.T) {
 		},
 		// REFILL not implemented
 		// RESTORE-INPUT not implemented
-		// ROLL not implemented
+		{
+			name: "ROLL",
+			code: `
+				T{ 1 2 3 2 ROLL -> 2 3 1 }T
+				T{ 1 2 1 ROLL -> 2 1 }T
+				T{ 4 5 6 0 ROLL -> 4 5 6 }T
+			`,
+		},
 		// S\" not implemented
 		// SAVE-INPUT not implemented
 		// SOURCE-ID not implemented
@@ -1887,7 +1894,13 @@ func TestDoubleSuite(t *testing.T) {
 
 func TestDoubleExtensionSuite(t *testing.T) {
 	tests := []suiteTest{
-		// 2ROT not implemented
+		{
+			name: "2ROT",
+			code: `
+				T{       1.       2. 3. 2ROT ->       2. 3.       1. }T
+				T{ MAX-2INT MIN-2INT 1. 2ROT -> MIN-2INT 1. MAX-2INT }T
+			`,
+		},
 		{
 			name: "2VALUE",
 			setup: `