aboutsummaryrefslogtreecommitdiff
path: root/include
diff options
context:
space:
mode:
authorUsama Arif <usama.arif@arm.com>2018-12-12 17:08:33 +0000
committerUsama Arif <usama.arif@arm.com>2019-02-19 17:07:48 +0000
commita5aa25af6514ff04721efce05e46b4daf8729a85 (patch)
treeedfa3429fd232129a838c6043c84928ddff63c60 /include
parentc9fe6fed4bcd930af4ccc487633b35e92d3cc288 (diff)
downloadtrusted-firmware-a-a5aa25af6514ff04721efce05e46b4daf8729a85.tar.gz
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>
Diffstat (limited to 'include')
-rw-r--r--include/arch/aarch32/asm_macros.S29
1 files changed, 28 insertions, 1 deletions
diff --git a/include/arch/aarch32/asm_macros.S b/include/arch/aarch32/asm_macros.S
index 8408804fbd..8cfa21231a 100644
--- a/include/arch/aarch32/asm_macros.S
+++ b/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 */