[Qemu-ppc] [PATCH v2 7/8] sm501: Do not clear read only bits when writing register

[BALATON Zoltan]

When writing a register that has read only bits besides reserved bits
we have to avoid changing read only bits that may have non zero
default values.

Signed-off-by: BALATON Zoltan <address@hidden>
---
 hw/display/sm501.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/hw/display/sm501.c b/hw/display/sm501.c
index e47be99..7ec1434 100644
--- a/hw/display/sm501.c
+++ b/hw/display/sm501.c
@@ -836,10 +836,10 @@ static void sm501_system_config_write(void *opaque, 
hwaddr addr,
 
     switch (addr) {
     case SM501_SYSTEM_CONTROL:
-        s->system_control = value & 0xE300B8F7;
+        s->system_control |= value & 0xEF00B8F7;
         break;
     case SM501_MISC_CONTROL:
-        s->misc_control = value & 0xFF7FFF20;
+        s->misc_control |= value & 0xFF7FFF10;
         break;
     case SM501_GPIO31_0_CONTROL:
         s->gpio_31_0_control = value;
@@ -853,7 +853,7 @@ static void sm501_system_config_write(void *opaque, hwaddr 
addr,
         s->dram_control |=  value & 0x7FFFFFC3;
         break;
     case SM501_ARBTRTN_CONTROL:
-        s->arbitration_control =  value & 0x37777777;
+        s->arbitration_control = value & 0x37777777;
         break;
     case SM501_IRQ_MASK:
         s->irq_mask = value;
-- 
2.7.6