diff options
Diffstat (limited to 'src/cmd/8g/gsubr.c')
| -rw-r--r-- | src/cmd/8g/gsubr.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/src/cmd/8g/gsubr.c b/src/cmd/8g/gsubr.c index 6bcc3eed84..d0c7310251 100644 --- a/src/cmd/8g/gsubr.c +++ b/src/cmd/8g/gsubr.c @@ -123,6 +123,41 @@ newplist(void) } void +clearstk(void) +{ + Plist *pl; + Prog *p1, *p2; + Node sp, di, cx, con; + + if(plast->firstpc->to.offset <= 0) + return; + + // reestablish context for inserting code + // at beginning of function. + pl = plast; + p1 = pl->firstpc; + p2 = p1->link; + pc = mal(sizeof(*pc)); + clearp(pc); + p1->link = pc; + + // zero stack frame + nodreg(&sp, types[tptr], D_SP); + nodreg(&di, types[tptr], D_DI); + nodreg(&cx, types[TUINT32], D_CX); + nodconst(&con, types[TUINT32], p1->to.offset / widthptr); + gins(ACLD, N, N); + gins(AMOVL, &sp, &di); + gins(AMOVL, &con, &cx); + gins(AREP, N, N); + gins(ASTOSL, N, N); + + // continue with original code. + gins(ANOP, N, N)->link = p2; + pc = P; +} + +void gused(Node *n) { gins(ANOP, n, N); // used |