Subject: [PATCH v7 28/28] powerpc sstep: Add support for prefixed fixed-point arithmetic

From: Jordan Niethe <[email-masked]>
Date: Fri, 1 May 2020 13:42:20 +1000

This adds emulation support for the following prefixed Fixed-Point
Arithmetic instructions:
  * Prefixed Add Immediate (paddi)

Reviewed-by: Balamuruhan S <[email-masked]>
Signed-off-by: Jordan Niethe <[email-masked]>
---
v3: Since we moved the prefixed loads/stores into the load/store switch
statement it no longer makes sense to have paddi in there, so move it
out.
---
 arch/powerpc/lib/sstep.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index d50fa2a78866..32e3ba742e55 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -1337,6 +1337,26 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
 
 	switch (opcode) {
 #ifdef __powerpc64__
+	case 1:
+		prefix_r = word & (1ul << 20);
+		ra = (suffix >> 16) & 0x1f;
+		rd = (suffix >> 21) & 0x1f;
+		op->reg = rd;
+		op->val = regs->gpr[rd];
+		suffixopcode = suffix >> 26;
+		prefixtype = (word >> 24) & 0x3;
+		switch (prefixtype) {
+		case 2:
+			if (prefix_r && ra)
+				return 0;
+			switch (suffixopcode) {
+			case 14:	/* paddi */
+				op->type = COMPUTE | PREFIXED;
+				op->val = mlsd_8lsd_ea(word, suffix, regs);
+				goto compute_done;
+			}
+		}
+		break;
 	case 2:		/* tdi */
 		if (rd & trap_compare(regs->gpr[ra], (short) word))
 			goto trap;
-- 
2.17.1