diff options
Diffstat (limited to 'newlib/libc/sys/d10v/crt0.S')
| -rw-r--r-- | newlib/libc/sys/d10v/crt0.S | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/newlib/libc/sys/d10v/crt0.S b/newlib/libc/sys/d10v/crt0.S new file mode 100644 index 0000000..e17f0a4 --- /dev/null +++ b/newlib/libc/sys/d10v/crt0.S @@ -0,0 +1,58 @@ + .text + .global _start + .type _start,@function + .stabs "crt0.S",100,0,0,_start + .stabs "int:t(0,1)=r(0,1);-32768;32767;",128,0,0,0 + .stabs "_start:F(0,1)",36,0,1,_start + +_start: + +; R14 always contains memory base address (0) + + ldi r14,0 + +; Set the USER stack pointer. + + ldi sp, 0x8000 ; SW + mvtc sp, psw ; psw <- SW + ldi sp, _stack + ldi r0,0 ; zero arguments + ldi r1,0 + +; Clear the BSS. Do it in two parts for efficiency: longwords first +; for most of it, then the remaining 0 to 3 bytes. + + ldi r2, __bss_start ; R2 = start of BSS + ldi r3, _end ; R3 = end of BSS + 1 + sub r3, r2 ; R3 = BSS size in bytes + mv r4, r3 + srli r4, 2 ; R4 = BSS size in longwords (rounded down) +loop1: + cmpeqi r4, 0 ; more longords to zero out? + brf0t.s endloop1 ; nope + st2w r0, @r2+ ; yep, zero out another longword + subi r4, 1 ; decrement count + bra.l loop1 ; go do some more + +endloop1: + and3 r4, r3, 3 ; get no. of remaining BSS bytes to clear +loop2: + cmpeqi r4, 0 ; more bytes to zero out? + brf0t.s endloop2 ; nope + stb r0, @r2 ; yep, zero out another byte + addi r2, 1 ; bump address + subi r4, 1 ; decrement count + bra.s loop2 ; go do some more +endloop2: + +; Call main, then stop simulator + + bl main + bl exit + stop +.Lstart: + .size _start,.Lstart-_start + .stabs "",36,0,0,.Lstart-_start + + .section .stack +_stack: .long 1 |