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[v11,45/46] mips_malta: Fix semihosting argument passing for nanoMIPS bare metal

Message ID 1534789014-8310-46-git-send-email-aleksandar.markovic@rt-rk.com
State New
Headers show
Series Add nanoMIPS support - core functionality and system mode | expand

Commit Message

Aleksandar Markovic Aug. 20, 2018, 6:16 p.m. UTC 
From: Stefan Markovic <smarkovic@wavecomp.com>

Fix passing argument for nanoMIPS bare metal related to the
semihosting regime.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Signed-off-by: Yongbok Kim <yongbok.kim@mips.com>
Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Signed-off-by: Stefan Markovic <smarkovic@wavecomp.com>
---
 hw/mips/mips_malta.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
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Patch

diff --git a/hw/mips/mips_malta.c b/hw/mips/mips_malta.c
index f261dd6..40041d5 100644
--- a/hw/mips/mips_malta.c
+++ b/hw/mips/mips_malta.c
@@ -630,8 +630,14 @@  static void write_bootloader_nanomips(uint8_t *base, int64_t run_addr,
                                 /* nop */
 
     /* to_here: */
-    stw_p(p++, 0x0080); stw_p(p++, 0x0002);
+    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));