I've tried what you suggested, linking the boot.rel first results in the
opposite effect, the _START area gets overwritten by the _CODE area.
Here a small showcase for the problem I'm having:
; boot.asm:
.globl HexToU8
.area _START (ABS,OVR)
.org 0
ld SP, #0xFFFF
call HexToU8
Loop:
jp Loop
.asciz "boot"
; numconv.asm:
.globl HexToU8
.area _CODE (REL,CON)
HexToU8:
ld A, #'A'
ret
TESTSTR:
.asciz "numconv"
$ sdasz80 -o numconv.asm
$ sdasz80 -o boot.asm
$ sdldz80 MemMonitor.ihx boot.rel numconv.rel -i
$ sdobjcopy -Iihex -Obinary --pad-to 65536 --gap-fill 255 MemMonitor.ihx
MemMonitor.bin
$ hexdump -C MemMonitor.bin
00000000 3e 41 c9 6e 75 6d 63 6f 6e 76 00 6f 74 00 ff ff
|>A.numconv.ot...|
00000010 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
|................|
*
00010000
As you can see, the linker overwrites the _START area with the _CODE area.
On 17-08-2016 11:09, Maarten Brock wrote:
>> Hello SDCC users,
>>
>>
>> I'm doing a project with the famous Z80 just for fun, and decided to use
>> the sdasz80 assembler. My project consists of multiple source files to
>> keep everything modular. I'm having a problem with the linking step.
>> I've 2 source files: boot.asm and numconv.asm:
>>
>>
>> ; boot.asm:
>> .globl HexToU8
>> .area _START (ABS)
>>
>> .org 0
>> ld SP, #0xFFFF
>> call HexToU8
>> ...
>>
>> ; numconv.asm:
>> .globl HexToU8
>> .area _CODE (REL,CON)
>>
>> HexToU8:
>> ...
>> ret
>>
>>
>> As you can see, the boot.asm uses absolute placement because it needs to
>> be placed at the begning of the memory (it needs to be executed first).
>> The numconv.asm uses relative placement instead (it can be at any memory
>> position provided that the HexToU8 symbol is correctly adjusted by the
>> linker).
>>
>>
>> To compile and link I invoke the folowing commands:
>>
>> $ sdasz80 -o src/numconv.asm
>> $ sdasz80 -o src/boot.asm
>> $ sdldz80 MemMonitor.ihx src/numconv.rel src/boot.rel -i
>> $ sdobjcopy -Iihex -Obinary --pad-to 65536 --gap-fill 255 MemMonitor.ihx
>> MemMonitor.bin
>>
>>
>> It seems to compile and link fine, but the final binary doesn't include
>> the numconv subroutines and the HexToU8 symbol assumes the value 0x0000.
>> With my understanding the linker tries to put the _CODE (REL, CON) area
>> at the 0x0000 address, but it gets overwritten with the _START (ABS)
>> area. How I tell the linker to put the _CODE area to any other available
>> address (not used by the _START area)?
> I'd start by linking boot.rel first.
>
> Maarten
>
>
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