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[32/35] hw/mips: Fix semihosting argument passing for nanoMIPS bare metal

Message ID 20180620120620.12806-33-yongbok.kim@mips.com
State New
Headers show
Series nanoMIPS | expand

Commit Message

Yongbok Kim June 20, 2018, 12:06 p.m. UTC 
From: Stefan Markovic <stefan.markovic@mips.com>

Fix semihosting argument passing for nanoMIPS bare metal

Signed-off-by: Yongbok Kim <yongbok.kim@mips.com>
---
 hw/mips/mips_malta.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)
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Patch

diff --git a/hw/mips/mips_malta.c b/hw/mips/mips_malta.c
index c4139d6..6207d83 100644
--- a/hw/mips/mips_malta.c
+++ b/hw/mips/mips_malta.c
@@ -642,7 +642,12 @@  static void write_bootloader_nanomips(uint8_t *base, int64_t run_addr,
     stw_p(p++, 0x8000); stw_p(p++, 0xc000); /* nop */
 
     /* to_here: */
-    stw_p(p++, 0x0080); stw_p(p++, 0x0002); /* li a0,2 */
+    if (semihosting_get_argc()) {
+        /* Preserve a0 content as arguments have been passed */
+        stw_p(p++, 0x8000); stw_p(p++, 0xc000); /* nop */
+    } else {
+        stw_p(p++, 0x0080); stw_p(p++, 0x0002); /* li a0,2 */
+    }
     stw_p(p++, 0xe3a0 | NM_HI1(ENVP_ADDR - 64));
     stw_p(p++, NM_HI2(ENVP_ADDR - 64));
                                 /* lui sp,%hi(ENVP_ADDR - 64) */