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[kernel] Use himem.sys method to enable A20 for greater 8042 compatibility #2798

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Merged
ghaerr merged 1 commit into from
Aug 5, 2026
Merged

[kernel] Use himem.sys method to enable A20 for greater 8042 compatibility #2798

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6 changes: 5 additions & 1 deletion elks/arch/i86/kernel/system.c
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Original file line number Diff line number Diff line change
Expand Up @@ -68,10 +68,14 @@ unsigned int INITPROC setup_arch(void)

arch_cpu = SETUP_CPU_TYPE;
#ifdef SYS_CAPS
sys_caps = SYS_CAPS; /* custom system capabilities */
sys_caps = SYS_CAPS; /* custom system capabilities */
#else
if (arch_cpu >= CPU_80286) /* 80286+ IBM PC/AT capabilities or Unknown CPU */
sys_caps = CAP_ALL;
#ifdef CONFIG_ARCH_IBMPC
else if (peekb(0x96, BIOSSEG) & 0x10)
sys_caps |= CAP_KBD_LEDS; /* 101/102 enhanced keyboard installed */
#endif
debug("arch %d sys_caps %02x\n", arch_cpu, sys_caps);
#endif

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4 changes: 2 additions & 2 deletions elks/arch/i86/lib/a20-ibm.inc
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Expand Up @@ -13,8 +13,8 @@
# USE_A20ASM - use Chris Giese A20.ASM method (send D0, read, OR 2, D1, write)
# USE_HIMEM_AT - use himem.sys PC AT method (send D1,DF,FF)
#define USE_BIOS
#define USE_A20ASM
//#define USE_HIMEM_AT
//#define USE_A20ASM
#define USE_HIMEM_AT

# Attempt to enable A20 address gate, return 0 on fail
enable_a20_gate:
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