Add memory-load instruction to Patio IR

3 files changed, 18 insertions, 5 deletions

diff --git a/src/main/java/org/shedlang/compiler/patio/PatioInstructionSerializer.java b/src/main/java/org/shedlang/compiler/patio/PatioInstructionSerializer.java
index 382c4125..fad162dd 100644
--- a/src/main/java/org/shedlang/compiler/patio/PatioInstructionSerializer.java
+++ b/src/main/java/org/shedlang/compiler/patio/PatioInstructionSerializer.java
@@ -1,9 +1,6 @@
 package org.shedlang.compiler.patio;
 
-import org.shedlang.compiler.patio.instructions.PatioAlloc;
-import org.shedlang.compiler.patio.instructions.PatioDiscard;
-import org.shedlang.compiler.patio.instructions.PatioInstruction;
-import org.shedlang.compiler.patio.instructions.PatioReturn;
+import org.shedlang.compiler.patio.instructions.*;
 import org.shedlang.compiler.treetext.Tree;
 
 import java.util.List;
@@ -40,6 +37,12 @@ public class PatioInstructionSerializer {
             case PatioDiscard discard ->
                 treeList(treeIdentifier("discard"));
 
+            case PatioMemoryLoad memoryLoad ->
+                treeList(
+                    treeIdentifier("memory-load"),
+                    treeNamed("offset", treeInt(memoryLoad.offset()))
+                );
+
             case PatioReturn return_ ->
                 treeList(treeIdentifier("return"));
         };
diff --git a/src/main/java/org/shedlang/compiler/patio/instructions/PatioInstruction.java b/src/main/java/org/shedlang/compiler/patio/instructions/PatioInstruction.java
index 6928d324..2083f0d3 100644
--- a/src/main/java/org/shedlang/compiler/patio/instructions/PatioInstruction.java
+++ b/src/main/java/org/shedlang/compiler/patio/instructions/PatioInstruction.java
@@ -2,6 +2,6 @@ package org.shedlang.compiler.patio.instructions;
 
 import org.shedlang.compiler.sources.Source;
 
-public sealed interface PatioInstruction permits PatioAlloc, PatioDiscard, PatioReturn {
+public sealed interface PatioInstruction permits PatioAlloc, PatioDiscard, PatioMemoryLoad, PatioReturn {
     Source source();
 }
diff --git a/src/main/java/org/shedlang/compiler/patio/instructions/PatioMemoryLoad.java b/src/main/java/org/shedlang/compiler/patio/instructions/PatioMemoryLoad.java
new file mode 100644
index 00000000..7068fcbe
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/patio/instructions/PatioMemoryLoad.java
@@ -0,0 +1,10 @@
+package org.shedlang.compiler.patio.instructions;
+
+import org.shedlang.compiler.sources.Source;
+
+/**
+ * Pop a value from the stack and assume it is a pointer. Load the value at the
+ * given offset from that pointer and push it onto the stack.
+ */
+public record PatioMemoryLoad(int offset, Source source) implements PatioInstruction {
+}