From: Matthias Welwarsky <matthias.welwarsky@sysgo.com>
Date: Tue, 15 Nov 2016 21:10:03 +0000 (+0100)
Subject: aarch64: optimize core state detection
X-Git-Url: https://git.sur5r.net/?p=openocd;a=commitdiff_plain;h=7ed0b6333ded06f1e517d7fd3e15a400c98dc357

aarch64: optimize core state detection

Replace loop by right-shift.
Inspired by patch from Alamy Liu

Change-Id: I1285f4f54c0695a93fa42e9863ed8ffa4de00f70
Signed-off-by: Matthias Welwarsky <matthias.welwarsky@sysgo.com>
Reviewed-on: http://openocd.zylin.com/3985
Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>
---

diff --git a/src/target/armv8_dpm.c b/src/target/armv8_dpm.c
index 56e2eb8f..ac53460e 100644
--- a/src/target/armv8_dpm.c
+++ b/src/target/armv8_dpm.c
@@ -51,17 +51,11 @@ enum arm_state armv8_dpm_get_core_state(struct arm_dpm *dpm)
 {
 	int el = (dpm->dscr >> 8) & 0x3;
 	int rw = (dpm->dscr >> 10) & 0xF;
-	int pos;
 
 	dpm->last_el = el;
 
-	/* find the first '0' in DSCR.RW */
-	for (pos = 3; pos >= 0; pos--) {
-		if ((rw & (1 << pos)) == 0)
-			break;
-	}
-
-	if (el > pos)
+	/* In Debug state, each bit gives the current Execution state of each EL */
+	if ((rw >> el) & 0b1)
 		return ARM_STATE_AARCH64;
 
 	return ARM_STATE_ARM;