diff --git a/cmd/vet/asmdecl.go b/cmd/vet/asmdecl.go
index 001b1770cc..c32ed9930d 100644
--- a/cmd/vet/asmdecl.go
+++ b/cmd/vet/asmdecl.go
@@ -33,6 +33,7 @@ type asmArch struct {
 	name      string
 	ptrSize   int
 	intSize   int
+	maxAlign  int
 	bigEndian bool
 }
 
@@ -55,14 +56,16 @@ type asmVar struct {
 }
 
 var (
-	asmArch386   = asmArch{"386", 4, 4, false}
-	asmArchArm   = asmArch{"arm", 4, 4, false}
-	asmArchAmd64 = asmArch{"amd64", 8, 8, false}
+	asmArch386      = asmArch{"386", 4, 4, 4, false}
+	asmArchArm      = asmArch{"arm", 4, 4, 4, false}
+	asmArchAmd64    = asmArch{"amd64", 8, 8, 8, false}
+	asmArchAmd64p32 = asmArch{"amd64p32", 4, 4, 8, false}
 
 	arches = []*asmArch{
 		&asmArch386,
 		&asmArchArm,
 		&asmArchAmd64,
+		&asmArchAmd64p32,
 	}
 )
 
@@ -234,13 +237,13 @@ func (f *File) asmParseDecl(decl *ast.FuncDecl) map[string]*asmFunc {
 				case "int32", "uint32", "float32":
 					size = 4
 				case "int64", "uint64", "float64":
-					align = arch.ptrSize
+					align = arch.maxAlign
 					size = 8
 				case "int", "uint":
 					size = arch.intSize
 				case "uintptr", "iword", "Word", "Errno", "unsafe.Pointer":
 					size = arch.ptrSize
-				case "string":
+				case "string", "ErrorString":
 					size = arch.ptrSize * 2
 					align = arch.ptrSize
 					kind = asmString
@@ -403,7 +406,7 @@ func (f *File) asmParseDecl(decl *ast.FuncDecl) map[string]*asmFunc {
 		offset = 0
 		addParams(decl.Type.Params.List)
 		if decl.Type.Results != nil && len(decl.Type.Results.List) > 0 {
-			offset += -offset & (arch.ptrSize - 1)
+			offset += -offset & (arch.maxAlign - 1)
 			addParams(decl.Type.Results.List)
 		}
 		fn.size = offset