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@@ -20,6 +20,7 @@
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╚─────────────────────────────────────────────────────────────────────────────*/
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// LISP meta-circular evaluator in a MBR
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+// Compatible with the original hardware
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.set ATOM_NIL, (kNil-kSymbols)<<1|1
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.set ATOM_QUOTE, (kQuote-kSymbols)<<1|1
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@@ -38,11 +39,6 @@
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.set ONE, %cx
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.set TWO, %bx
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-////////////////////////////////////////////////////////////////////////////////
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-// Currently requires i386+ in real mode
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-// Can be easily tuned for the IBM PC XT
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-// Quoth xed -r -isa-set -i sectorlisp.o
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-
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.section .text,"ax",@progbits
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.type kSymbols,@object
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.type _begin,@function
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@@ -73,10 +69,10 @@ _begin: push %cs # memory model ds=es=ss=cs
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cld # clear direction flag
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rep stosb # memset(0x8000,0,0x8000)
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push %ds # cx is now zero
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-# cli # disable interrupts
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+ cli # disable interrupts
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pop %ss # disable nonmaskable interrupts
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mov %ax,%sp # use null pointer as our stack
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-# sti # enable interrupts
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+ sti # enable interrupts
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inc ONE # ++cx
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mov ONE,TWO
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inc TWO
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@@ -181,10 +177,10 @@ GetChar:
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# ah is bios scancode
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# al is ascii character
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PutChar:
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-# push %bp # original ibm pc scroll up bug
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+ push %bp # original ibm pc scroll up bug
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mov $0x0e,%ah # teletype output al cp437
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int $0x10 # vidya service
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-# pop %bp # preserves al
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+ pop %bp # preserves al
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cmp $'\r',%al # don't clobber stuff
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jne .ret
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mov $'\n',%al
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Justine Tunney