From 635ee55a5ddb7371c8af4d9195a288415cc973fa Mon Sep 17 00:00:00 2001
From: gbeauche <>
Date: Tue, 4 Jul 2006 04:21:02 +0000
Subject: [PATCH] Fix floating-point single precision load/store (VEX's
 jm-ppc-test -f)

---
 .../kpx_cpu/src/cpu/ppc/ppc-dyngen-ops.cpp    | 12 ++-----
 .../src/kpx_cpu/src/cpu/ppc/ppc-execute.cpp   | 21 +++++-------
 .../src/kpx_cpu/src/cpu/ppc/ppc-execute.hpp   | 33 +++++++++++++++++++
 3 files changed, 44 insertions(+), 22 deletions(-)

diff --git a/SheepShaver/src/kpx_cpu/src/cpu/ppc/ppc-dyngen-ops.cpp b/SheepShaver/src/kpx_cpu/src/cpu/ppc/ppc-dyngen-ops.cpp
index 75557572..0932eb6b 100644
--- a/SheepShaver/src/kpx_cpu/src/cpu/ppc/ppc-dyngen-ops.cpp
+++ b/SheepShaver/src/kpx_cpu/src/cpu/ppc/ppc-dyngen-ops.cpp
@@ -237,19 +237,11 @@ DEFINE_REG(31);
 #endif
 
 #ifndef do_load_single
-#define do_load_single(REG, EA) do {			\
-	any_register *x = (any_register *)&FD;		\
-	x->i = vm_read_memory_4(EA);				\
-	REG = (double)x->f;							\
-} while (0)
+#define do_load_single(REG, EA) REG##_dw = fp_load_single_convert(vm_read_memory_4(EA))
 #endif
 
 #ifndef do_store_single
-#define do_store_single(REG, EA) do {			\
-	any_register *x = (any_register *)&FD;		\
-	x->f = (float)REG;							\
-	vm_write_memory_4(EA, x->i);				\
-} while (0)
+#define do_store_single(REG, EA) vm_write_memory_4(EA, fp_store_single_convert(REG##_dw))
 #endif
 
 #ifndef do_load_double
diff --git a/SheepShaver/src/kpx_cpu/src/cpu/ppc/ppc-execute.cpp b/SheepShaver/src/kpx_cpu/src/cpu/ppc/ppc-execute.cpp
index f5176acc..82fa9a36 100644
--- a/SheepShaver/src/kpx_cpu/src/cpu/ppc/ppc-execute.cpp
+++ b/SheepShaver/src/kpx_cpu/src/cpu/ppc/ppc-execute.cpp
@@ -616,24 +616,21 @@ void powerpc_cpu::execute_fp_loadstore(uint32 opcode)
 	const uint32 a = RA::get(this, opcode);
 	const uint32 b = RB::get(this, opcode);
 	const uint32 ea = a + b;
+	uint64 v;
 
 	if (LD) {
 		if (DB)
-			operand_fp_dw_RD::set(this, opcode, vm_read_memory_8(ea));
-		else {
-			any_register x;
-			x.i = vm_read_memory_4(ea);
-			operand_fp_RD::set(this, opcode, (double)x.f);
-		}
+			v = vm_read_memory_8(ea);
+		else
+			v = fp_load_single_convert(vm_read_memory_4(ea));
+		operand_fp_dw_RD::set(this, opcode, v);
 	}
 	else {
+		v = operand_fp_dw_RS::get(this, opcode);
 		if (DB)
-			vm_write_memory_8(ea, operand_fp_dw_RS::get(this, opcode));
-		else {
-			any_register x;
-			x.f = (float)operand_fp_RS::get(this, opcode);
-			vm_write_memory_4(ea, x.i);
-		}
+			vm_write_memory_8(ea, v);
+		else
+			vm_write_memory_4(ea, fp_store_single_convert(v));
 	}
 
 	if (UP)
diff --git a/SheepShaver/src/kpx_cpu/src/cpu/ppc/ppc-execute.hpp b/SheepShaver/src/kpx_cpu/src/cpu/ppc/ppc-execute.hpp
index 158d6ead..7aa689c0 100644
--- a/SheepShaver/src/kpx_cpu/src/cpu/ppc/ppc-execute.hpp
+++ b/SheepShaver/src/kpx_cpu/src/cpu/ppc/ppc-execute.hpp
@@ -191,6 +191,39 @@ DEFINE_HELPER(do_execute_divide, (uint32 RA, uint32 RB))
 	RETURN(RD);
 }
 
+/**
+ *		FP load/store
+ **/
+
+// C.6 Floating-Point Load Instructions
+static inline uint64 fp_load_single_convert(uint32 v)
+{
+	// XXX we currently use the native floating-point capabilities
+	any_register x;
+	x.i = v;
+	x.d = (double)x.f;
+	return x.j;
+}
+
+// C.7 Floating-Point Store Instructions
+static inline uint32 fp_store_single_convert(uint64 v)
+{
+	int exp = (v >> 52) & 0x7ff;
+	if (exp < 874 || exp > 896) {
+		// No denormalization required (or "undefined" behaviour)
+		// WORD[0 - 1] = frS[0 - 1]
+		// WORD[2 - 31] = frS[5 - 34]
+		return (uint32)(((v >> 32) & 0xc0000000) | ((v >> 29) & 0x3fffffff));
+	}
+
+	// Handle denormalization (874 <= frS[1 - 11] <= 896
+	// XXX we currently use the native floating-point capabilities
+	any_register x;
+	x.j = v;
+	x.f = (float)x.d;
+	return x.i;
+}
+
 /**
  *		FP classification
  **/