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changeset 603:8c7b63f9fab8

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Fix reg-indirect mode for RBP/R13
author Michael Pavone <pavone@retrodev.com>
date Fri, 26 Dec 2014 19:36:41 -0800
parents 452ad0b42afa
children 39d7d463ed5b
files gen_x86.c
diffstat 1 files changed, 11 insertions(+), 4 deletions(-) [+]
line wrap: on
line diff
--- a/gen_x86.c	Fri Dec 26 15:46:53 2014 -0800
+++ b/gen_x86.c	Fri Dec 26 19:36:41 2014 -0800
@@ -322,10 +322,17 @@
 		opcode |= BIT_SIZE;
 	}
 	*(out++) = opcode | dir;
-	*(out++) = MODE_REG_INDIRECT | base | (reg << 3);
-	if (base == RSP) {
-		//add SIB byte, with no index and RSP as base
-		*(out++) = (RSP << 3) | RSP;
+	if (base == RBP) {
+		//add a dummy 8-bit displacement since MODE_REG_INDIRECT with
+		//an R/M field of RBP selects RIP, relative addressing
+		*(out++) = MODE_REG_DISPLACE8 | base | (reg << 3);
+		*(out++) = 0;
+	} else {
+		*(out++) = MODE_REG_INDIRECT | base | (reg << 3);
+		if (base == RSP) {
+			//add SIB byte, with no index and RSP as base
+			*(out++) = (RSP << 3) | RSP;
+		}
 	}
 	code->cur = out;
 }