PEEK and POKE Library: Difference between revisions

Revision as of 02:19, 23 January 2023

This header allows you to peek and poke bytes, words, and dwords in QB64. The functions seem to work okay when used with signed variables also. For example, I am able to assign the return of peekw~% to an INTEGER without problem. Regards, Michael Calkins

Create PeekPoke.h text file in the QB64 folder:

/*
peek and poke for bytes, words, and dwords in qb64
public domain, sept 2011, michael calkins
https://www.tapatalk.com/groups/qbasic/viewtopic.php?p=188921#p188921
*/

unsigned char peekb(void * p)
{return *(unsigned char *)p;}

unsigned short int peekw(void * p)
{return *(unsigned short int *)p;}

unsigned long int peekd(void * p)
{return *(unsigned long int *)p;}

void pokeb(void * p, unsigned char n)
{*(unsigned char *)p = n;}

void pokew(void * p, unsigned short int n)
{*(unsigned short int *)p = n;}

void poked(void * p, unsigned long int n)
{*(unsigned long int *)p = n;}

Public domain, Sept 2011, Michael Calkins

PeekPoke.BAS

' peek and poke for bytes, words, and dwords in qb64
' requires peekpoke.h
' public domain, sept 2011, michael calkins

DECLARE CUSTOMTYPE LIBRARY "peekpoke"
    FUNCTION peekb~%% (BYVAL p AS _UNSIGNED _OFFSET) 'Byte
    FUNCTION peekw~% (BYVAL p AS _UNSIGNED _OFFSET)  'Integer(Word)
    FUNCTION peekd~& (BYVAL p AS _UNSIGNED _OFFSET)  'Long(Dword)
    SUB pokeb (BYVAL p AS _UNSIGNED _OFFSET, BYVAL n AS _UNSIGNED _BYTE)
    SUB pokew (BYVAL p AS _UNSIGNED _OFFSET, BYVAL n AS _UNSIGNED INTEGER)
    SUB poked (BYVAL p AS _UNSIGNED _OFFSET, BYVAL n AS _UNSIGNED LONG)
END DECLARE

' examples:

DIM buffer AS STRING * 16
DIM ptr AS _UNSIGNED _OFFSET

buffer = "abcd---- i-ptrs"
ptr = _OFFSET(buffer)

PRINT buffer

pokeb ptr + &HA, &H3
PRINT buffer

pokew ptr + 5, &H3FA8
PRINT buffer

poked ptr + 4, &HDBB2B1B0
PRINT buffer

poked ptr, CVL("QB64")
poked ptr + 4, &H2020011A
PRINT buffer

PRINT "0x" + HEX$(peekb~%%(ptr + 1))
PRINT "0x" + HEX$(peekw~%(ptr + 2))
PRINT "0x" + HEX$(peekd~&(ptr + 9))

END

Note: These functions and statements use a variable name reference pointer in memory instead of DEF SEG.

See also:

Navigation: Main Page with Articles and Tutorials Keyword Reference - Alphabetical Keyword Reference - By usage Report a broken link

@@ Line 40: / Line 40: @@
      {{Cl|FUNCTION}} peekw~% ({{Cl|BYVAL}} p {{Cl|AS}} {{Cl|_UNSIGNED}} {{Cl|_OFFSET}})  'Integer(Word)
      {{Cl|FUNCTION}} peekd~& ({{Cl|BYVAL}} p {{Cl|AS}} {{Cl|_UNSIGNED}} {{Cl|_OFFSET}})  'Long(Dword)
      {{Cl|SUB}} pokeb ({{Cl|BYVAL}} p {{Cl|AS}} {{Cl|_UNSIGNED}} {{Cl|_OFFSET}}, {{Cl|BYVAL}} n {{Cl|AS}} {{Cl|_UNSIGNED}} {{Cl|_BYTE}})
      {{Cl|SUB}} pokew ({{Cl|BYVAL}} p {{Cl|AS}} {{Cl|_UNSIGNED}} {{Cl|_OFFSET}}, {{Cl|BYVAL}} n {{Cl|AS}} {{Cl|_UNSIGNED}} {{Cl|INTEGER}})
      {{Cl|SUB}} poked ({{Cl|BYVAL}} p {{Cl|AS}} {{Cl|_UNSIGNED}} {{Cl|_OFFSET}}, {{Cl|BYVAL}} n {{Cl|AS}} {{Cl|_UNSIGNED}} {{Cl|LONG}})
@@ Line 72: / Line 72: @@
 {{Cl|PRINT}} "0x" + {{Cl|HEX$}}(peekd~&(ptr + 9))
-{{Cl|END}} '' ''
+{{Cl|END}}
 {{CodeEnd}}
 <center>'''Note: These functions and statements use a variable name reference pointer in memory instead of [[DEF SEG]].'''</center>

PEEK and POKE Library: Difference between revisions

Revision as of 02:19, 23 January 2023

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