1 files changed, 45 insertions, 0 deletions
diff --git a/arch/powerpc/math-emu/fsub.c b/arch/powerpc/math-emu/fsub.c
new file mode 100644
index 000000000..47a8f847b
--- /dev/null
+++ b/arch/powerpc/math-emu/fsub.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/uaccess.h>
+
+#include <asm/sfp-machine.h>
+#include <math-emu/soft-fp.h>
+#include <math-emu/double.h>
+
+int
+fsub(void *frD, void *frA, void *frB)
+{
+	FP_DECL_D(A);
+	FP_DECL_D(B);
+	FP_DECL_D(R);
+	FP_DECL_EX;
+
+#ifdef DEBUG
+	printk("%s: %p %p %p\n", __func__, frD, frA, frB);
+#endif
+
+	FP_UNPACK_DP(A, frA);
+	FP_UNPACK_DP(B, frB);
+
+#ifdef DEBUG
+	printk("A: %ld %lu %lu %ld (%ld)\n", A_s, A_f1, A_f0, A_e, A_c);
+	printk("B: %ld %lu %lu %ld (%ld)\n", B_s, B_f1, B_f0, B_e, B_c);
+#endif
+
+	if (B_c != FP_CLS_NAN)
+		B_s ^= 1;
+
+	if (A_s != B_s && A_c == FP_CLS_INF && B_c == FP_CLS_INF)
+		FP_SET_EXCEPTION(EFLAG_VXISI);
+
+	FP_ADD_D(R, A, B);
+
+#ifdef DEBUG
+	printk("D: %ld %lu %lu %ld (%ld)\n", R_s, R_f1, R_f0, R_e, R_c);
+#endif
+
+	__FP_PACK_D(frD, R);
+
+	return FP_CUR_EXCEPTIONS;
+}