From 4ee07ea6b0286ed265e06bdbf09550d3b97fe4f0 Mon Sep 17 00:00:00 2001
From: Luciano Ciccariello <Xeeynamo@users.noreply.github.com>
Date: Sun, 19 May 2024 12:29:04 +0100
Subject: [PATCH] Add support for `seb`/`seh` instructions from mips32r2 (#273)

---
 m2c/arch_mips.py                        |  4 ++++
 tests/end_to_end/seb-seh/seb-mwcc-out.c |  8 ++++++++
 tests/end_to_end/seb-seh/seb-mwcc.s     | 19 +++++++++++++++++++
 tests/end_to_end/seb-seh/seh-mwcc-out.c |  8 ++++++++
 tests/end_to_end/seb-seh/seh-mwcc.s     | 19 +++++++++++++++++++
 5 files changed, 58 insertions(+)
 create mode 100644 tests/end_to_end/seb-seh/seb-mwcc-out.c
 create mode 100644 tests/end_to_end/seb-seh/seb-mwcc.s
 create mode 100644 tests/end_to_end/seb-seh/seh-mwcc-out.c
 create mode 100644 tests/end_to_end/seb-seh/seh-mwcc.s

diff --git a/m2c/arch_mips.py b/m2c/arch_mips.py
index 5f9d00ef..fe4f1c60 100644
--- a/m2c/arch_mips.py
+++ b/m2c/arch_mips.py
@@ -62,6 +62,7 @@
     as_intish,
     as_s64,
     as_sintish,
+    as_type,
     as_u32,
     as_u64,
     as_uintish,
@@ -1662,6 +1663,9 @@ def eval_fn(s: NodeState, a: InstrArgs) -> None:
         # Unaligned loads
         "lwl": lambda a: handle_lwl(a),
         "lwr": lambda a: handle_lwr(a),
+        # Sign extend
+        "seb": lambda a: as_type(a.reg(1), Type.s8(), silent=False),
+        "seh": lambda a: as_type(a.reg(1), Type.s16(), silent=False),
     }
 
     @staticmethod
diff --git a/tests/end_to_end/seb-seh/seb-mwcc-out.c b/tests/end_to_end/seb-seh/seb-mwcc-out.c
new file mode 100644
index 00000000..68221e9a
--- /dev/null
+++ b/tests/end_to_end/seb-seh/seb-mwcc-out.c
@@ -0,0 +1,8 @@
+s8 foo(s8);                                         /* extern */
+
+s8 test(s32 arg0) {
+    s32 sp10;
+
+    sp10 = arg0;
+    return (s8) (foo((s8) sp10) + 1);
+}
diff --git a/tests/end_to_end/seb-seh/seb-mwcc.s b/tests/end_to_end/seb-seh/seb-mwcc.s
new file mode 100644
index 00000000..db025250
--- /dev/null
+++ b/tests/end_to_end/seb-seh/seb-mwcc.s
@@ -0,0 +1,19 @@
+glabel test
+addiu   sp,sp,-0x20
+sw      ra,0xc(sp)
+sw      s0,8(sp)
+sw      a0,0x10(sp)
+lw      v0,0x10(sp)
+seb     a0,v0
+jal     foo
+nop
+seb     v0,v0
+addiu   v0,v0,1
+seb     v0,v0
+seb     s0,v0
+move    v0,s0
+lw      ra,0xc(sp)
+lw      s0,8(sp)
+addiu   sp,sp,0x20
+jr      ra
+nop
diff --git a/tests/end_to_end/seb-seh/seh-mwcc-out.c b/tests/end_to_end/seb-seh/seh-mwcc-out.c
new file mode 100644
index 00000000..e9ac06a0
--- /dev/null
+++ b/tests/end_to_end/seb-seh/seh-mwcc-out.c
@@ -0,0 +1,8 @@
+s16 foo(s16);                                       /* extern */
+
+s16 test(s32 arg0) {
+    s32 sp10;
+
+    sp10 = arg0;
+    return (s16) (foo((s16) sp10) + 1);
+}
diff --git a/tests/end_to_end/seb-seh/seh-mwcc.s b/tests/end_to_end/seb-seh/seh-mwcc.s
new file mode 100644
index 00000000..44e3b95d
--- /dev/null
+++ b/tests/end_to_end/seb-seh/seh-mwcc.s
@@ -0,0 +1,19 @@
+glabel test
+addiu   sp,sp,-0x20
+sw      ra,0xc(sp)
+sw      s0,8(sp)
+sw      a0,0x10(sp)
+lw      v0,0x10(sp)
+seh     a0,v0
+jal     foo
+nop
+seh     v0,v0
+addiu   v0,v0,1
+seh     v0,v0
+seh     s0,v0
+move    v0,s0
+lw      ra,0xc(sp)
+lw      s0,8(sp)
+addiu   sp,sp,0x20
+jr      ra
+nop