#119 -0x0100, perhaps preprocessor or compiler bug, HC08 core

[xiaolaba]

simple test code for the purpose.
To form 32bit integer in RAM area, however ~() will renders result with -0x00000100.
why ? a bug ?

// sdcc 3.6.0
// build script,
// sdcc -mhc08 --data-loc 0x80 --code-loc 0xEE00 --stack-loc 0xFF sdcc360_bug.c -o sdcc360_bug.S19

// perhaps bug, why ~() and -0x0100
// 2018-OCT-28

#define MOD 0xBEBE0000

#include <mc68hc908qy.h>

volatile unsigned long int value;

void main() {

// supposedly same long value
  value = (0xBEBE7B84);
  value = (0xBEBE0000 + 0x7B84);
  value = (0xBEBE0000 + 0x7B00 + 0x84);
  value = (MOD        + 0x7B00 + 0x84);
  value = (0xBEBE7B00 +          ~0x7B);   // it is odd, -0x0100     
  value = (0xBEBE0000 + 0x7B00 + ~0x7B);   // it is odd, -0x0100
  value = (MOD        + 0x7B00 + ~0x7B);   // it is odd, -0x0100

// supposedly same long
  value = (0xBEBEFF01);
  value = (0xBEBE0000 + 0xFF01);
  value = (0xBEBE0000 + 0xFF00 + 0x01);
  value = (MOD        + 0xFF00 + 0x01);    
  value = (0xBEBE0000 + 0xFF00 + ~0xFE);   // it is odd, -0x0100
  value = (MOD        + 0xFF00 + ~0xFE);   // it is odd, -0x0100

}
```






asm show the same odd thing,
 i.e. #0x7b is expected,
 EE5E A6 7B         [ 2]  232   lda #0x7b

this one is about #0x7b-1 = 0x7a
final result is always -0x00000100,
 EE6E A6 7A         [ 2]  241   lda #0x7a

                        227 ;sdcc360_bug.c:17: value = (MOD        + 0x7B00 + 0x84);

EE56 45 00 80 [ 3] 228 ldhx #_value
EE59 A6 BE [ 2] 229 lda #0xbe
EE5B F7 [ 2] 230 sta ,x
EE5C E7 01 [ 3] 231 sta 1,x
EE5E A6 7B [ 2] 232 lda #0x7b
EE60 E7 02 [ 3] 233 sta 2,x
EE62 A6 84 [ 2] 234 lda #0x84
EE64 E7 03 [ 3] 235 sta 3,x
236 ;sdcc360_bug.c:18: value = (0xBEBE7B00 + ~0x7B); // it is odd, -0x0100
EE66 45 00 80 [ 3] 237 ldhx #_value
EE69 A6 BE [ 2] 238 lda #0xbe
EE6B F7 [ 2] 239 sta ,x
EE6C E7 01 [ 3] 240 sta 1,x
EE6E A6 7A [ 2] 241 lda #0x7a
EE70 E7 02 [ 3] 242 sta 2,x
EE72 A6 84 [ 2] 243 lda #0x84
EE74 E7 03 [ 3] 244 sta 3,x
~~~

[xiaolaba]

latest release of sdcc 3.8.0 has gone through same compiling process, the problem persisted,

;--------------------------------------------------------
; File Created by SDCC : free open source ANSI-C Compiler
; Version 3.8.0 #10562 (MINGW64)
;--------------------------------------------------------
    .module sdcc360_bug
    .optsdcc -mhc08

    .area HOME    (CODE)
    .area GSINIT0 (CODE)
    .area GSINIT  (CODE)
    .area GSFINAL (CODE)
    .area CSEG    (CODE)
    .area XINIT   (CODE)
    .area CONST   (CODE)
    .area DSEG    (PAG)
    .area OSEG    (PAG, OVR)
    .area XSEG
    .area XISEG
    .area   CODEIVT (ABS)
    .org    0xfffe
    .dw __sdcc_gs_init_startup

    .area GSINIT0
__sdcc_gs_init_startup:
    ldhx    #0x0100
    txs
    jsr __sdcc_external_startup
    beq __sdcc_init_data
    jmp __sdcc_program_startup
__sdcc_init_data:
; _hc08_genXINIT() start
        ldhx #0
00001$:
        cphx #l_XINIT
        beq  00002$
        lda  s_XINIT,x
        sta  s_XISEG,x
        aix  #1
        bra  00001$
00002$:
; _hc08_genXINIT() end
    .area GSFINAL
    jmp __sdcc_program_startup

    .area CSEG
__sdcc_program_startup:
    jsr _main
    bra .
;--------------------------------------------------------
; Public variables in this module
;--------------------------------------------------------
    .globl _main
    .globl _value
    .globl _COPCTL
    .globl _OSCTRIMVAL
    .globl _FLBPR
    .globl _LVISR
    .globl _BRKSCR
    .globl _BRK
    .globl _BRKL
    .globl _BRKH
    .globl _FLCR
    .globl _INT3
    .globl _INT2
    .globl _INT1
    .globl _BFCF
    .globl _BRKAR
    .globl _SRSR
    .globl _BSR
    .globl _ADICLK
    .globl _ADR
    .globl _ADSCR
    .globl _OSCTRIM
    .globl _OSCSTAT
    .globl _TCH1
    .globl _TCH1L
    .globl _TCH1H
    .globl _TSC1
    .globl _TCH0
    .globl _TCH0L
    .globl _TCH0H
    .globl _TSC0
    .globl _TMOD
    .globl _TMODL
    .globl _TMODH
    .globl _TCNT
    .globl _TCNTL
    .globl _TCNTH
    .globl _TSC
    .globl _CONFIG1
    .globl _CONFIG2
    .globl _INTSCR
    .globl _KBIER
    .globl _KBSCR
    .globl _PTBPUE
    .globl _PTAPUE
    .globl _DDRB
    .globl _DDRA
    .globl _PTB
    .globl _PTA
;--------------------------------------------------------
; ram data
;--------------------------------------------------------
    .area DSEG    (PAG)
_PTA    =   0x0000
_PTB    =   0x0001
_DDRA   =   0x0004
_DDRB   =   0x0005
_PTAPUE =   0x000b
_PTBPUE =   0x000c
_KBSCR  =   0x001a
_KBIER  =   0x001b
_INTSCR =   0x001d
_CONFIG2    =   0x001e
_CONFIG1    =   0x001f
_TSC    =   0x0020
_TCNTH  =   0x0021
_TCNTL  =   0x0022
_TCNT   =   0x0021
_TMODH  =   0x0023
_TMODL  =   0x0024
_TMOD   =   0x0023
_TSC0   =   0x0025
_TCH0H  =   0x0026
_TCH0L  =   0x0027
_TCH0   =   0x0026
_TSC1   =   0x0028
_TCH1H  =   0x0029
_TCH1L  =   0x002a
_TCH1   =   0x0029
_OSCSTAT    =   0x0036
_OSCTRIM    =   0x0038
_ADSCR  =   0x003c
_ADR    =   0x003e
_ADICLK =   0x003f
;--------------------------------------------------------
; overlayable items in ram 
;--------------------------------------------------------
;--------------------------------------------------------
; absolute ram data
;--------------------------------------------------------
    .area IABS    (ABS)
    .area IABS    (ABS)
;--------------------------------------------------------
; absolute external ram data
;--------------------------------------------------------
    .area XABS    (ABS)
;--------------------------------------------------------
; external initialized ram data
;--------------------------------------------------------
    .area XISEG
;--------------------------------------------------------
; extended address mode data
;--------------------------------------------------------
    .area XSEG
_BSR    =   0xfe00
_SRSR   =   0xfe01
_BRKAR  =   0xfe02
_BFCF   =   0xfe03
_INT1   =   0xfe04
_INT2   =   0xfe05
_INT3   =   0xfe06
_FLCR   =   0xfe08
_BRKH   =   0xfe09
_BRKL   =   0xfe0a
_BRK    =   0xfe09
_BRKSCR =   0xfe0b
_LVISR  =   0xfe0c
_FLBPR  =   0xffbe
_OSCTRIMVAL =   0xffc0
_COPCTL =   0xffff
_value::
    .ds 4
;--------------------------------------------------------
; global & static initialisations
;--------------------------------------------------------
    .area HOME    (CODE)
    .area GSINIT  (CODE)
    .area GSFINAL (CODE)
    .area GSINIT  (CODE)
;--------------------------------------------------------
; Home
;--------------------------------------------------------
    .area HOME    (CODE)
    .area HOME    (CODE)
;--------------------------------------------------------
; code
;--------------------------------------------------------
    .area CSEG    (CODE)
;------------------------------------------------------------
;Allocation info for local variables in function 'main'
;------------------------------------------------------------
;sdcc360_bug.c:14: void main() {
;   -----------------------------------------
;    function main
;   -----------------------------------------
;   Register assignment is optimal.
;   Stack space usage: 0 bytes.
_main:
;sdcc360_bug.c:17: value = (0xBEBE7B84);
    ldhx    #_value
    lda #0xbe
    sta ,x
    sta 1,x
    lda #0x7b
    sta 2,x
    lda #0x84
    sta 3,x
;sdcc360_bug.c:18: value = (0xBEBE0000 + 0x7B84);
    ldhx    #_value
    lda #0xbe
    sta ,x
    sta 1,x
    lda #0x7b
    sta 2,x
    lda #0x84
    sta 3,x
;sdcc360_bug.c:19: value = (0xBEBE0000 + 0x7B00 + 0x84);
    ldhx    #_value
    lda #0xbe
    sta ,x
    sta 1,x
    lda #0x7b
    sta 2,x
    lda #0x84
    sta 3,x
;sdcc360_bug.c:20: value = (MOD        + 0x7B00 + 0x84);
    ldhx    #_value
    lda #0xbe
    sta ,x
    sta 1,x
    lda #0x7b
    sta 2,x
    lda #0x84
    sta 3,x
;sdcc360_bug.c:21: value = (0xBEBE7B00 +          ~0x7B);   // it is odd, -0x0100     
    ldhx    #_value
    lda #0xbe
    sta ,x
    sta 1,x
    lda #0x7a
    sta 2,x
    lda #0x84
    sta 3,x
;sdcc360_bug.c:22: value = (0xBEBE0000 + 0x7B00 + ~0x7B);   // it is odd, -0x0100
    ldhx    #_value
    lda #0xbe
    sta ,x
    sta 1,x
    lda #0x7a
    sta 2,x
    lda #0x84
    sta 3,x
;sdcc360_bug.c:23: value = (MOD        + 0x7B00 + ~0x7B);   // it is odd, -0x0100
    ldhx    #_value
    lda #0xbe
    sta ,x
    sta 1,x
    lda #0x7a
    sta 2,x
    lda #0x84
    sta 3,x
;sdcc360_bug.c:26: value = (0xBEBEFF01);
    ldhx    #_value
    lda #0xbe
    sta ,x
    sta 1,x
    lda #0xff
    sta 2,x
    lda #0x01
    sta 3,x
;sdcc360_bug.c:27: value = (0xBEBE0000 + 0xFF01);
    ldhx    #_value
    lda #0xbe
    sta ,x
    sta 1,x
    lda #0xff
    sta 2,x
    lda #0x01
    sta 3,x
;sdcc360_bug.c:28: value = (0xBEBE0000 + 0xFF00 + 0x01);
    ldhx    #_value
    lda #0xbe
    sta ,x
    sta 1,x
    lda #0xff
    sta 2,x
    lda #0x01
    sta 3,x
;sdcc360_bug.c:29: value = (MOD        + 0xFF00 + 0x01);    
    ldhx    #_value
    lda #0xbe
    sta ,x
    sta 1,x
    lda #0xff
    sta 2,x
    lda #0x01
    sta 3,x
;sdcc360_bug.c:30: value = (0xBEBE0000 + 0xFF00 + ~0xFE);   // it is odd, -0x0100
    ldhx    #_value
    lda #0xbe
    sta ,x
    sta 1,x
    lda #0xfe
    sta 2,x
    lda #0x01
    sta 3,x
;sdcc360_bug.c:31: value = (MOD        + 0xFF00 + ~0xFE);   // it is odd, -0x0100
    ldhx    #_value
    lda #0xbe
    sta ,x
    sta 1,x
    lda #0xfe
    sta 2,x
    lda #0x01
    sta 3,x
;sdcc360_bug.c:33: }
    rts
    .area CSEG    (CODE)
    .area CONST   (CODE)
    .area XINIT   (CODE)
    .area CABS    (ABS,CODE)

[Philipp Klaus Krause]

~0xfe is not 0x84.

Philipp

P.S.: (uint8_t)(~0xfe) is 0x84.

[xiaolaba]

sorry. could not follow, do you have complete example.
there are perhaps 1's complement and the 2's complement, i.e.,

0x7b,
1's complement = 0x84 (NOT 0x7B)
2's complement = 0x85 (-0x7B)

[Maarten Brock]

The constant is an integer, not an unsigned char.
~0x7B == ~0x007B == 0xFF84