diff options
Diffstat (limited to 'thumb2divmod.s')
| -rw-r--r-- | thumb2divmod.s | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/thumb2divmod.s b/thumb2divmod.s new file mode 100644 index 0000000..c2c205f --- /dev/null +++ b/thumb2divmod.s @@ -0,0 +1,169 @@ +
+ .arch armv7-a
+ .fpu vfpv3-d16
+ .text
+
+ .globl divide
+divide:
+ eor r12,r3,r4
+ cmp r4,#0
+ neglt r4,r4
+ cmp r3,#0
+ neglt r3,r3
+
+ cmp r4,#32
+ bls divide_by_small_number
+
+ clz r1,r4
+ clz r2,r3
+ rsb r1,r1,#31-5-11
+ add r1,r1,r2
+ mov r2,#0
+
+ cmp r1,#32-5-11
+ bhs divide_large_result
+
+ add r1,r1,r1,lsl #1
+ add pc,pc,r1,lsl #2
+ nop
+
+ .set shift,32-5-11
+ .rept 32-5-11
+ .set shift,shift-1
+ subs r1,r3,r4,lsl #shift
+ movcs r3,r1
+ orrcs r2,r2,#1<<shift
+ .endr
+
+ mov r4,r2
+ cmp r12,#0
+ neglt r4,r4
+ ldr pc,[sp],#4
+
+divide_large_result:
+ bpl divide_result_0
+
+ vmov s13,r3
+ vmov s15,r4
+ vcvt.f64.u32 d6,s13
+ vcvt.f64.u32 d7,s15
+ vdiv.f64 d7,d6,d7
+ vcvt.u32.f64 s15,d7
+ vmov r4,s15
+ cmp r12,#0
+ neglt r4,r4
+ ldr pc,[sp],#4
+
+divide_result_0:
+ mov r4,#0
+ ldr pc,[sp],#4
+
+divide_by_small_number:
+ add r1,pc,r4,lsl #3
+ ldrb r4,[r1,#(div_mod_table+1)-(divide_by_small_number+8)]
+ ldr r2,[r1,#(div_mod_table+4)-(divide_by_small_number+8)]
+ ldrb r1,[r1,#div_mod_table-(divide_by_small_number+8)]
+ adds r3,r3,r4
+ umullcc r4,r2,r3,r2
+ lsr r4,r2,r1
+ cmp r12,#0
+ neglt r4,r4
+ ldr pc,[sp],#4
+
+ .globl modulo
+modulo:
+ cmp r4,#0
+ neglt r4,r4
+ movs r12,r3
+ neglt r3,r3
+
+ cmp r4,#32
+ bls modulo_of_small_number
+
+ clz r1,r4
+ clz r2,r3
+ rsb r1,r1,#31-5-11
+ add r1,r1,r2
+
+ cmp r1,#32-5-11
+ bhs modulo_large_divide_result
+
+ add pc,pc,r1,lsl #3
+ nop
+
+ .set shift,32
+ .rept 32
+ .set shift,shift-1
+ subs r1,r3,r4,lsl #shift
+ movcs r3,r1
+ .endr
+
+modulo_large_divide_result:
+ bpl modulo_divide_result_0
+
+ vmov s13,r3
+ vmov s15,r4
+ vcvt.f64.u32 d6,s13
+ vcvt.f64.u32 d7,s15
+ vdiv.f64 d7,d6,d7
+ vcvt.u32.f64 s15,d7
+ vmov r2,s15
+ b modulo_from_quotient
+
+modulo_divide_result_0:
+ mov r4,r3
+ cmp r12,#0
+ neglt r4,r4
+ ldr pc,[sp],#4
+
+modulo_of_small_number:
+ add r1,pc,r4,lsl #3
+ ldrb r0,[r1,#(div_mod_table+1)-(modulo_of_small_number+8)]
+ ldr r2,[r1,#(div_mod_table+4)-(modulo_of_small_number+8)]
+ ldrb r1,[r1,#div_mod_table-(modulo_of_small_number+8)]
+ adds r14,r3,r0
+ umullcc r0,r2,r14,r2
+ lsr r2,r2,r1
+modulo_from_quotient:
+@ mls r4,r4,r2,r3
+ neg r3,r3
+ mla r4,r4,r2,r3
+ cmp r12,#0
+ neglt r4,r4
+ ldr pc,[sp],#4
+
+div_mod_table:
+ .long 0,0
+ .long 0x100,0xffffffff
+ .long 0,0x80000000
+ .long 1,0xaaaaaaab
+ .long 0,0x40000000
+ .long 2,0xcccccccd
+ .long 2,0xaaaaaaab
+ .long 0x102,0x92492492
+ .long 0,0x20000000
+ .long 1,0x38e38e39
+ .long 3,0xcccccccd
+ .long 3,0xba2e8ba3
+ .long 3,0xaaaaaaab
+ .long 2,0x4ec4ec4f
+ .long 0x103,0x92492492
+ .long 3,0x88888889
+ .long 0,0x10000000
+ .long 4,0xf0f0f0f1
+ .long 2,0x38e38e39
+ .long 0x104,0xd79435e5
+ .long 4,0xcccccccd
+ .long 0x104,0xc30c30c3
+ .long 4,0xba2e8ba3
+ .long 4,0xb21642c9
+ .long 4,0xaaaaaaab
+ .long 3,0x51eb851f
+ .long 3,0x4ec4ec4f
+ .long 0x104,0x97b425ed
+ .long 0x104,0x92492492
+ .long 4,0x8d3dcb09
+ .long 4,0x88888889
+ .long 0x104,0x84210842
+ .long 0,0x08000000
+
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