From 86968d95f1696cbcc53d6068913611d8386a7183 Mon Sep 17 00:00:00 2001
From: Elliott Hughes <enh@google.com>
Date: Tue, 21 May 2024 21:25:50 +0000
Subject: [PATCH] setjmp_test: riscv64 does have callee-save fp registers.

The setjmp implementation is correct, but this comment was wrong, and we were missing the implementation of the test. This would be slightly simpler if we enabled Zfa in the build system and qemu, but this works for now.

Change-Id: Iad32771019584beacd8b35138ac2bf4c0a14c903
---
 tests/setjmp_test.cpp | 53 +++++++++++++++++++++++++++++++++++--------
 1 file changed, 44 insertions(+), 9 deletions(-)

diff --git a/tests/setjmp_test.cpp b/tests/setjmp_test.cpp
index 0de0a01ba..946928517 100644
--- a/tests/setjmp_test.cpp
+++ b/tests/setjmp_test.cpp
@@ -174,6 +174,9 @@ TEST(setjmp, sigsetjmp_1_signal_mask) {
   }
 }
 
+#if defined(__arm__) || defined(__aarch64__)
+// arm and arm64 have the same callee save fp registers (8-15),
+// but use different instructions for accessing them.
 #if defined(__arm__)
 #define SET_FREG(n, v) asm volatile("vmov.f64 d"#n ", #"#v : : : "d"#n)
 #define GET_FREG(n) ({ double _r; asm volatile("fcpyd %P0, d"#n : "=w"(_r) : :); _r;})
@@ -183,21 +186,53 @@ TEST(setjmp, sigsetjmp_1_signal_mask) {
 #define GET_FREG(n) ({ double _r; asm volatile("fmov %0, d"#n : "=r"(_r) : :); _r; })
 #define CLEAR_FREG(n) asm volatile("fmov d"#n ", xzr" : : : "d"#n)
 #endif
-
-#if defined(__arm__) || defined(__aarch64__)
 #define SET_FREGS \
   SET_FREG(8, 8.0); SET_FREG(9, 9.0); SET_FREG(10, 10.0); SET_FREG(11, 11.0); \
-  SET_FREG(12, 12.0); SET_FREG(13, 13.0); SET_FREG(14, 14.0); SET_FREG(15, 15.0);
+  SET_FREG(12, 12.0); SET_FREG(13, 13.0); SET_FREG(14, 14.0); SET_FREG(15, 15.0)
 #define CLEAR_FREGS \
   CLEAR_FREG(8); CLEAR_FREG(9); CLEAR_FREG(10); CLEAR_FREG(11); \
-  CLEAR_FREG(12); CLEAR_FREG(13); CLEAR_FREG(14); CLEAR_FREG(15);
+  CLEAR_FREG(12); CLEAR_FREG(13); CLEAR_FREG(14); CLEAR_FREG(15)
 #define CHECK_FREGS \
-    EXPECT_EQ(8.0, GET_FREG(8)); EXPECT_EQ(9.0, GET_FREG(9)); \
-    EXPECT_EQ(10.0, GET_FREG(10)); EXPECT_EQ(11.0, GET_FREG(11)); \
-    EXPECT_EQ(12.0, GET_FREG(12)); EXPECT_EQ(13.0, GET_FREG(13)); \
-    EXPECT_EQ(14.0, GET_FREG(14)); EXPECT_EQ(15.0, GET_FREG(15));
+  EXPECT_EQ(8.0, GET_FREG(8)); EXPECT_EQ(9.0, GET_FREG(9)); \
+  EXPECT_EQ(10.0, GET_FREG(10)); EXPECT_EQ(11.0, GET_FREG(11)); \
+  EXPECT_EQ(12.0, GET_FREG(12)); EXPECT_EQ(13.0, GET_FREG(13)); \
+  EXPECT_EQ(14.0, GET_FREG(14)); EXPECT_EQ(15.0, GET_FREG(15))
+
+#elif defined(__riscv)
+// riscv64 has callee save registers fs0-fs11.
+// TODO: use Zfa to get 1.0 rather than the one_p trick.
+#define SET_FREGS \
+  double one = 1, *one_p = &one; \
+  asm volatile("fmv.d.x fs0, zero ; fld fs1, (%0) ; \
+                fadd.d fs2, fs1, fs1 ; fadd.d fs3, fs2, fs1 ; \
+                fadd.d fs4, fs3, fs1 ; fadd.d fs5, fs4, fs1 ; \
+                fadd.d fs6, fs5, fs1 ; fadd.d fs7, fs6, fs1 ; \
+                fadd.d fs8, fs7, fs1 ; fadd.d fs9, fs8, fs1 ; \
+                fadd.d fs10, fs9, fs1 ; fadd.d fs11, fs10, fs1" \
+               : \
+               : "r"(one_p) \
+               : "fs0", "fs1", "fs2", "fs3", "fs4", "fs5", \
+                  "fs6", "fs7", "fs8", "fs9", "fs10", "fs11")
+#define CLEAR_FREGS \
+  asm volatile("fmv.d.x fs0, zero ; fmv.d.x fs1, zero ; \
+                fmv.d.x fs2, zero ; fmv.d.x fs3, zero ; \
+                fmv.d.x fs4, zero ; fmv.d.x fs5, zero ; \
+                fmv.d.x fs6, zero ; fmv.d.x fs7, zero ; \
+                fmv.d.x fs8, zero ; fmv.d.x fs9, zero ; \
+                fmv.d.x fs10, zero ; fmv.d.x fs11, zero" \
+               : : : "fs0", "fs1", "fs2", "fs3", "fs4", "fs5", \
+                     "fs6", "fs7", "fs8", "fs9", "fs10", "fs11")
+#define GET_FREG(n) ({ double _r; asm volatile("fmv.d %0, fs"#n : "=f"(_r) : :); _r; })
+#define CHECK_FREGS \
+  EXPECT_EQ(0.0, GET_FREG(0)); EXPECT_EQ(1.0, GET_FREG(1)); \
+  EXPECT_EQ(2.0, GET_FREG(2)); EXPECT_EQ(3.0, GET_FREG(3)); \
+  EXPECT_EQ(4.0, GET_FREG(4)); EXPECT_EQ(5.0, GET_FREG(5)); \
+  EXPECT_EQ(6.0, GET_FREG(6)); EXPECT_EQ(7.0, GET_FREG(7)); \
+  EXPECT_EQ(8.0, GET_FREG(8)); EXPECT_EQ(9.0, GET_FREG(9)); \
+  EXPECT_EQ(10.0, GET_FREG(10)); EXPECT_EQ(11.0, GET_FREG(11))
+
 #else
-/* The other architectures don't save/restore fp registers. */
+// x86 and x86-64 don't save/restore fp registers.
 #define SET_FREGS
 #define CLEAR_FREGS
 #define CHECK_FREGS