| .text |
| .global __clone |
| .type __clone, %function |
| __clone: |
| # int clone( |
| # fn, a = r2 |
| # stack, b = r3 |
| # flags, c = r4 |
| # arg, d = r5 |
| # ptid, e = r6 |
| # tls, f = *(r15+160) |
| # ctid) g = *(r15+168) |
| # |
| # pseudo C code: |
| # tid = syscall(SYS_clone,b,c,e,g,f); |
| # if (!tid) syscall(SYS_exit, a(d)); |
| # return tid; |
| |
| # create initial stack frame for new thread |
| nill %r3, 0xfff8 |
| aghi %r3, -160 |
| lghi %r0, 0 |
| stg %r0, 0(%r3) |
| |
| # save fn and arg to child stack |
| stg %r2, 8(%r3) |
| stg %r5, 16(%r3) |
| |
| # shuffle args into correct registers and call SYS_clone |
| lgr %r2, %r3 |
| lgr %r3, %r4 |
| lgr %r4, %r6 |
| lg %r5, 168(%r15) |
| lg %r6, 160(%r15) |
| svc 120 |
| |
| # if error or if we're the parent, return |
| ltgr %r2, %r2 |
| bnzr %r14 |
| |
| # we're the child. call fn(arg) |
| lg %r1, 8(%r15) |
| lg %r2, 16(%r15) |
| basr %r14, %r1 |
| |
| # call SYS_exit. exit code is already in r2 from fn return value |
| svc 1 |
