[XEN RFC PATCH 02/40] xen/arm: Print a 64-bit number in hex from early uart

[Wei Chen <wei.chen@xxxxxxx>]

Current putn function that is using for early print
only can print low 32-bit of AArch64 register. This
will lose some important messages while debugging
with early console. For example:
(XEN) Bringing up CPU5
- CPU 0000000100000100 booting -
Will be truncated to
(XEN) Bringing up CPU5
- CPU 00000100 booting -

In this patch, we increased the print loops and shift
bits to make putn print 64-bit number.

Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
---
 xen/arch/arm/arm64/head.S | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/xen/arch/arm/arm64/head.S b/xen/arch/arm/arm64/head.S
index aa1f88c764..b32639d7d6 100644
--- a/xen/arch/arm/arm64/head.S
+++ b/xen/arch/arm/arm64/head.S
@@ -862,17 +862,18 @@ puts:
         ret
 ENDPROC(puts)
 
-/* Print a 32-bit number in hex.  Specific to the PL011 UART.
+/* Print a 64-bit number in hex.  Specific to the PL011 UART.
  * x0: Number to print.
  * x23: Early UART base address
  * Clobbers x0-x3 */
+#define PRINT_MASK 0xf000000000000000
 putn:
         adr   x1, hex
-        mov   x3, #8
+        mov   x3, #16
 1:
         early_uart_ready x23, 2
-        and   x2, x0, #0xf0000000    /* Mask off the top nybble */
-        lsr   x2, x2, #28
+        and   x2, x0, #PRINT_MASK    /* Mask off the top nybble */
+        lsr   x2, x2, #60
         ldrb  w2, [x1, x2]           /* Convert to a char */
         early_uart_transmit x23, w2
         lsl   x0, x0, #4             /* Roll it through one nybble at a time */
-- 
2.25.1