Division functionality for cores that dont have divide hardware.

Cortex a5 doesnt support hardware division such as sdiv and udiv commands.
This commit adds a software division function in assembly as well as include
appropriate files for software divison.

The software division algorithm is a modified version obtained from:
http://www.keil.com/support/man/docs/armasm/armasm_dom1359731155623.htm



Change-Id: Ib405a330da5f1cea1e68e07e7b520edeef9e2652
Signed-off-by: Usama Arif <usama.arif@arm.com>

drivers/arm/pl011/aarch32/pl011_console.S

@@ -63,7 +63,14 @@ func console_pl011_core_init
 	/* Program the baudrate */
 	/* Divisor =  (Uart clock * 4) / baudrate */
 	lsl	r1, r1, #2
+#if (ARM_ARCH_MAJOR == 7) && !defined(ARMV7_SUPPORTS_VIRTUALIZATION)
+	push	{r0,r3}
+	softudiv	r0,r1,r2,r3
+	mov	r1, r0
+	pop	{r0,r3}
+#else
 	udiv	r2, r1, r2
+#endif
 	/* IBRD = Divisor >> 6 */
 	lsr	r1, r2, #6
 	/* Write the IBRD */

include/arch/aarch32/asm_macros.S

@@ -78,7 +78,7 @@
 	 * Clobber: r14, r1, r2
 	 */
 	.macro get_my_mp_stack _name, _size
-	bl  plat_my_core_pos
+	bl	plat_my_core_pos
 	ldr r2, =(\_name + \_size)
 	mov r1, #\_size
 	mla r0, r0, r1, r2
@@ -189,4 +189,31 @@
 		.endif
 	.endm
 
+	/*
+	 * Helper macro for carrying out division in software when
+	 * hardware division is not suported. \top holds the dividend
+	 * in the function call and the remainder after
+	 * the function is executed. \bot holds the divisor. \div holds
+	 * the quotient and \temp is a temporary registed used in calcualtion.
+	 * The division algorithm has been obtained from:
+	 * http://www.keil.com/support/man/docs/armasm/armasm_dom1359731155623.htm
+	 */
+	.macro	softudiv	div:req,top:req,bot:req,temp:req
+
+	mov     \temp, \bot
+	cmp     \temp, \top, lsr #1
+div1:
+	movls   \temp, \temp, lsl #1
+	cmp     \temp, \top, lsr #1
+	bls     div1
+	mov     \div, #0
+
+div2:
+	cmp     \top, \temp
+	subcs   \top, \top,\temp
+	ADC     \div, \div, \div
+	mov     \temp, \temp, lsr #1
+	cmp     \temp, \bot
+	bhs     div2
+	.endm
 #endif /* ASM_MACROS_S */