Print error message in pop_frame when the frame stack is empty

kernel/main.68k

@@ -1,6 +1,7 @@
 .global main
 main:
   move.l #inital_stack, a7 | Load the initial stack pointer
+  jsr term_init
   jsr pmem_init
   move.l #0x1000, d0
   jsr push_page

kernel/pmem.68k

@@ -42,8 +42,13 @@ move.l mmu_tlb_clear_addr, a0 | Clear the TLB entry for the mapping page
 move.l #map_page, (a0)
 rts
 pop_no_page:
+move.l #oom_error_str, a0
+jsr term_println
 stop #2700
 
+.data
+oom_error_str: .asciz "Out of physical memory"
+
 .bss
 mmu_tlb_clear_addr:
 .ds.b 4

kernel/term.68k

@@ -0,0 +1,33 @@
+.global term_init
+term_init:
+move.b #0x3, d0 | Get the pointer to the terminal card
+jsr find_first_card
+move.l a0, term_io_base
+rts
+
+| Prints the string pointed to by a0
+| Clobbers d0, a1
+.global term_print
+term_print:
+move.l term_io_base, a1
+term_print_loop:
+move.b (a0)+, d0
+cmpi.b #0, d0
+beq.b term_print_done
+move.b d0, (a1)
+bra.b term_print
+term_print_done:
+rts
+
+| Prints the string pointed to by a0 followed by a newline
+| Clobbers d0, a1
+.global term_println
+term_println:
+bsr.b term_print
+move.b #'\n, (a1)
+rts
+
+.bss
+
+term_io_base:
+.ds.b 4