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Add division operator support #27

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2 changes: 1 addition & 1 deletion README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -129,7 +129,7 @@ unary = deref identifier
| "(" expr ")"
| identifier
| integer
op = "+" | "-" | "&" | "|" | "^" | "<<" | ">>"
op = "+" | "-" | "*" | "/" | "&" | "|" | "^" | "<<" | ">>"
| "==" | "!=" | "<" | ">" | "<=" | ">="
```

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28 changes: 28 additions & 0 deletions examples/test_division.c
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Original file line number Diff line number Diff line change
@@ -0,0 +1,28 @@
int x;
int y;
int result;

void test_division()
{
x = 100;
y = 3;
result = x / y;

print_num = result;
print_i16();
print_newline();

x = 50;
y = 5;
result = x / y;

print_num = result;
print_i16();
print_newline();
}

void _start()
{
test_division();
while( 1 ){ }
}
2 changes: 2 additions & 0 deletions lint/lint.c
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Expand Up @@ -47,6 +47,7 @@ typedef int64_t i64;
_( TOK_SUB, "-", 65533 )\
_( TOK_ADD, "+", 65531 )\
_( TOK_MUL, "*", 65530 )\
_( TOK_DIV, "/", 65535 )\
_( TOK_OR, "|", 76 )\
_( TOK_XOR, "^", 46 )\
_( TOK_SHL, "<<", 132 )\
Expand Down Expand Up @@ -405,6 +406,7 @@ static bool tok_oper_is(void)
tok_kw_is(TOK_ADD) ||
tok_kw_is(TOK_SUB) ||
tok_kw_is(TOK_MUL) ||
tok_kw_is(TOK_DIV) ||
tok_kw_is(TOK_ADDR) || // "AND" in this context
tok_kw_is(TOK_OR) ||
tok_kw_is(TOK_XOR) ||
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17 changes: 15 additions & 2 deletions sectorc.s
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Expand Up @@ -24,6 +24,7 @@
%define TOK_SUB 65533
%define TOK_ADD 65531
%define TOK_MUL 65530
%define TOK_DIV 65535
%define TOK_AND 65526
%define TOK_OR 76
%define TOK_XOR 46
Expand Down Expand Up @@ -247,7 +248,18 @@ _found:

pop bx ; restore 16-bit of machine-code
cmp bh,0xc0 ; detect the special case for comparison ops
je emit_cmp_op
cmp bh,0xd0 ; detect division op
jne emit_op

; division operator inline
mov ax,0xd231 ; code for "xor dx,dx"
stosw ; emit
mov ax,0xf1f7 ; code for "div cx"
stosw ; emit
pop ds
ret

emit_cmp_op:
mov ax,0xc839 ; code for "cmp ax,cx"
stosw ; emit
Expand All @@ -258,7 +270,7 @@ emit_cmp_op:
;; [fall-through]

emit_op:
mov ax,bx
xchg ax,bx ; 1 byte instead of mov ax,bx (2 bytes)
stosw ; emit machine code for op
pop ds
ret
Expand Down Expand Up @@ -402,7 +414,8 @@ getch_done:
binary_oper_tbl:
dw TOK_ADD,0xc103 ; add ax,cx
dw TOK_SUB,0xc12b ; sub ax,cx
dw TOK_MUL,0xe1f7 ; mul ax,cx
dw TOK_MUL,0xe1f7 ; mul cx
dw TOK_DIV,0xd0f1 ; div cx (marker: 0xd0, low byte is F1 for "div cx")
dw TOK_AND,0xc123 ; and ax,cx
dw TOK_OR,0xc10b ; or ax,cx
dw TOK_XOR,0xc133 ; xor ax,cx
Expand Down