Subversion Repositories NedoOS

# file opened: relocation_mem_read.asm
 1    0000                  DEVICE ZXSPECTRUM48
 2    0000                  ORG $8000
 3    8000
 4    8000                  ; generally speaking, the `{<adr>}` operator is cancelling relocation
 5    8000                  ; of <adr> expression and operates in absolute way with the assembling-time
 6    8000                  ; address and memory content - seems this way it yields most logical outcomes
 7    8000
 8    8000                  RELOCATE_START
 9    8000 34 12        label1: DW  0x1234
10    8002 00 80        label2: DW  label1              ; should be relocated
11    8004
12    8004                      IF 0x1234 == {label1}   ; should be true
13    8004 21 02 80                 ld  hl,label2       ; should be relocated
14    8007                      ENDIF
15    8007                      IF label1 == {label2}   ; should be true (relocation unstability doesn't matter)
16    8007 11 00 80                 ld  de,label1       ; should be relocated
17    800A                      ENDIF
18    800A
19    800A 21 34 12             ld  hl,{label1}         ; regular 0x1234 value (reads the correct one always)
20    800D
21    800D                  ; ! this lost "needs relocation" property by indirection: be careful when using {adr}
22    800D 11 00 80             ld  de,{label2}
23    8010
24    8010                  ; this should always evaluate to true (not affected by relocation juggling)
25    8010 FF                   DB  0x1234 == {label1}
26    8011
27    8011 34 92                DW  {label1} + label1           ; should be relocated (0x1234 + label1)
relocation_mem_read.asm(28): warning[relunstable]: Relocation makes one of the expressions unstable, resulting machine code is not relocatable
28    8013 34                   DB  low ({label1} + label1)     ; should warn (byte(0x1234 + label1) is affected)
29    8014
30    8014                  ; byte-reading variants use the same technique
31    8014 FF                   DB  0x34 == {b label1}          ; should be true
32    8015 34 80                DW  {b label1} + label1         ; should be relocated
relocation_mem_read.asm(33): warning[relunstable]: Relocation makes one of the expressions unstable, resulting machine code is not relocatable
33    8017 34                   DB  low ({b label1} + label1)   ; should warn
34    8018
35    8018                  RELOCATE_END
36    8018
37    8018 02 80 05 80      RELOCATE_TABLE
37    801C 08 80 11 80
37    8020 15 80
38    8022
# file closed: relocation_mem_read.asm

Value    Label
------ - -----------------------------------------------------------
0x8000   label1
0x8002   label2
0x0005 X relocate_count
0x000A X relocate_size