| .text |
| .global __clone |
| .type __clone, %function |
| __clone: |
| # int clone(fn, stack, flags, arg, ptid, tls, ctid) |
| # a b c d e f g |
| # 3 4 5 6 7 8 9 |
| # pseudo C code: |
| # tid = syscall(SYS_clone,c,b,e,f,g); |
| # if (!tid) syscall(SYS_exit, a(d)); |
| # return tid; |
| |
| # SYS_clone = 120 |
| # SYS_exit = 1 |
| |
| # store non-volatile regs r30, r31 on stack in order to put our |
| # start func and its arg there |
| stwu 30, -16(1) |
| stw 31, 4(1) |
| |
| # save r3 (func) into r30, and r6(arg) into r31 |
| mr 30, 3 |
| mr 31, 6 |
| |
| # create initial stack frame for new thread |
| clrrwi 4, 4, 4 |
| li 0, 0 |
| stwu 0, -16(4) |
| |
| #move c into first arg |
| mr 3, 5 |
| #mr 4, 4 |
| mr 5, 7 |
| mr 6, 8 |
| mr 7, 9 |
| |
| # move syscall number into r0 |
| li 0, 120 |
| |
| sc |
| |
| # check for syscall error |
| bns+ 1f # jump to label 1 if no summary overflow. |
| #else |
| neg 3, 3 #negate the result (errno) |
| 1: |
| # compare sc result with 0 |
| cmpwi cr7, 3, 0 |
| |
| # if not 0, jump to end |
| bne cr7, 2f |
| |
| #else: we're the child |
| #call funcptr: move arg (d) into r3 |
| mr 3, 31 |
| #move r30 (funcptr) into CTR reg |
| mtctr 30 |
| # call CTR reg |
| bctrl |
| # mov SYS_exit into r0 (the exit param is already in r3) |
| li 0, 1 |
| sc |
| |
| 2: |
| |
| # restore stack |
| lwz 30, 0(1) |
| lwz 31, 4(1) |
| addi 1, 1, 16 |
| |
| blr |
| |
