allocStackTop size
= do { stk_usg <- getStkUsage
; let push_virt_sp = virtSp stk_usg + size
; setStkUsage (stk_usg { virtSp = push_virt_sp,
allocStackTop size
= do { stk_usg <- getStkUsage
; let push_virt_sp = virtSp stk_usg + size
; setStkUsage (stk_usg { virtSp = push_virt_sp,