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Diffstat (limited to '05')
-rw-r--r--05/codegen.b167
-rw-r--r--05/main.c10
2 files changed, 164 insertions, 13 deletions
diff --git a/05/codegen.b b/05/codegen.b
index 7dd7f37..d5ec907 100644
--- a/05/codegen.b
+++ b/05/codegen.b
@@ -662,12 +662,44 @@ function emit_jae_rel32
code_output += 4
return
+function emit_cmp_rax_rbx
+ ; 48 39 d8
+ *2code_output = 0x3948
+ code_output += 2
+ *1code_output = 0xd8
+ code_output += 1
+ return
+
function emit_comisd_xmm0_xmm1
; 66 0f 2f c1
*4code_output = 0xc12f0f66
code_output += 4
return
+#define COMPARISON_E 0x4
+#define COMPARISON_NE 0x5
+#define COMPARISON_L 0xc
+#define COMPARISON_G 0xf
+#define COMPARISON_LE 0xe
+#define COMPARISON_GE 0xd
+#define COMPARISON_B 0x2
+#define COMPARISON_A 0x7
+#define COMPARISON_BE 0x6
+#define COMPARISON_AE 0x3
+
+; emits two instructions:
+; setC al
+; movzx rax, al
+function emit_setC_rax
+ ; 0f 9C c0 48 0f b6 c0
+ argument comparison
+ local a
+ a = 0xc0b60f48c0900f
+ a |= comparison < 8
+ *8code_output = a
+ code_output += 7
+ return
+
; make sure you put the return value in the proper place before calling this
function generate_return
emit_mov_reg(REG_RSP, REG_RBP)
@@ -1436,7 +1468,78 @@ function generate_push_address_of_expression
expr += 8
return expr
-
+; pop the top two things off the stack of type `type` and compare them
+function generate_stack_compare
+ argument statement
+ argument type
+ local p
+ p = types + type
+
+ emit_add_rsp_imm32(16) ; add rsp, 16
+
+ ; NB: we do float comparisons as double comparisons (see function comparison_type)
+ if *1p == TYPE_DOUBLE goto stack_compare_double
+ if *1p > TYPE_UNSIGNED_LONG goto stack_compare_bad
+
+ emit_mov_rax_qword_rsp_plus_imm32(-16) ; mov rax, [rsp-16] (second operand)
+ emit_mov_reg(REG_RBX, REG_RAX) ; mov rbx, rax
+ emit_mov_rax_qword_rsp_plus_imm32(-8) ; mov rax, [rsp-8] (first operand)
+ emit_cmp_rax_rbx() ; cmp rax, rbx
+ return
+
+ :stack_compare_bad
+ die(.str_stack_compare_bad)
+ :str_stack_compare_bad
+ string Bad types passed to generate_stack_compare()
+ byte 0
+ :stack_compare_double
+ emit_mov_rax_qword_rsp_plus_imm32(-8) ; mov rax, [rsp-8] (first operand)
+ emit_movq_xmm0_rax() ; movq xmm0, rax
+ emit_mov_rax_qword_rsp_plus_imm32(-16) ; mov rax, [rsp-16] (second operand)
+ emit_movq_xmm1_rax() ; movq xmm1, rax
+ emit_comisd_xmm0_xmm1() ; comisd xmm0, xmm1
+ return
+
+; given that expr is a comparison expression, which type should both operands be converted to?
+function comparison_type
+ argument statement
+ argument expr
+ local type1
+ local type2
+ expr += 8
+
+ type1 = expr + 4
+ type1 = *4type1
+ expr = expression_get_end(expr)
+ type2 = expr + 4
+ type2 = *4type2
+
+ type1 += types
+ type1 = *1type1
+ type2 += types
+ type2 = *1type2
+
+ ; do float comparisons as double comparisons to make things simpler
+ if type1 == TYPE_FLOAT goto return_type_double
+ if type2 == TYPE_FLOAT goto return_type_double
+
+ if type1 == TYPE_POINTER goto return_type_unsigned_long
+ if type2 == TYPE_POINTER goto return_type_unsigned_long
+ return expr_binary_type_usual_conversions(statement, type1, type2)
+
+; is this comparison expression a comparison between unsigned integers or floats?
+function comparison_is_unsigned
+ argument statement
+ argument expr
+ local type
+ type = comparison_type(statement, expr)
+ type += types
+ type = *1type
+ if type > TYPE_UNSIGNED_LONG goto return_1 ; double comparisons use setb/seta not setl/setg
+ type &= 1
+ if type == 0 goto return_1
+ return 0
+
; `statement` is used for errors
; returns pointer to end of expression
function generate_push_expression
@@ -1446,6 +1549,7 @@ function generate_push_expression
local c
local d
local p
+ local comparison
local addr1
local addr2
local type
@@ -1475,6 +1579,12 @@ function generate_push_expression
if c == EXPRESSION_BITWISE_XOR goto generate_bitwise_xor
if c == EXPRESSION_LSHIFT goto generate_lshift
if c == EXPRESSION_RSHIFT goto generate_rshift
+ if c == EXPRESSION_EQ goto generate_eq
+ if c == EXPRESSION_NEQ goto generate_neq
+ if c == EXPRESSION_LT goto generate_lt
+ if c == EXPRESSION_GT goto generate_gt
+ if c == EXPRESSION_LEQ goto generate_leq
+ if c == EXPRESSION_GEQ goto generate_geq
if c == EXPRESSION_ASSIGN goto generate_assign
if c == EXPRESSION_ASSIGN_ADD goto generate_assign_add
if c == EXPRESSION_ASSIGN_SUB goto generate_assign_sub
@@ -1850,13 +1960,56 @@ function generate_push_expression
p = expr + 4
expr = generate_push_expression(statement, expr)
generate_stack_compare_against_zero(statement, *4p)
- emit_je_rel32(7) ; je +7 (2 bytes for xor eax, eax; 5 bytes for jmp +10)
- emit_zero_rax() ; xor eax, eax
- emit_jmp_rel32(10) ; jmp +10 (10 bytes for mov rax, 1)
- emit_mov_rax_imm64(1) ; mov rax, 1
- emit_push_rax() ; push rax
+ emit_setC_rax(COMPARISON_E) ; sete al ; movzx rax, al
+ emit_push_rax() ; push rax
+ return expr
+ :generate_eq
+ comparison = COMPARISON_E
+ goto generate_comparison
+ :generate_neq
+ comparison = COMPARISON_NE
+ goto generate_comparison
+ :generate_lt
+ b = comparison_is_unsigned(statement, expr)
+ if b != 0 goto comparison_b
+ comparison = COMPARISON_L
+ goto generate_comparison
+ :comparison_b
+ comparison = COMPARISON_B
+ goto generate_comparison
+ :generate_leq
+ b = comparison_is_unsigned(statement, expr)
+ if b != 0 goto comparison_be
+ comparison = COMPARISON_LE
+ goto generate_comparison
+ :comparison_be
+ comparison = COMPARISON_BE
+ goto generate_comparison
+ :generate_gt
+ b = comparison_is_unsigned(statement, expr)
+ if b != 0 goto comparison_a
+ comparison = COMPARISON_G
+ goto generate_comparison
+ :comparison_a
+ comparison = COMPARISON_A
+ goto generate_comparison
+ :generate_geq
+ b = comparison_is_unsigned(statement, expr)
+ if b != 0 goto comparison_ae
+ comparison = COMPARISON_GE
+ goto generate_comparison
+ :comparison_ae
+ comparison = COMPARISON_AE
+ goto generate_comparison
+ :generate_comparison
+ c = comparison_type(statement, expr)
+ expr += 8
+ expr = generate_push_expression_casted(statement, expr, c)
+ expr = generate_push_expression_casted(statement, expr, c)
+ generate_stack_compare(statement, c)
+ emit_setC_rax(comparison)
+ emit_push_rax()
return expr
-
:generate_conditional
expr += 8
p = expr + 4
diff --git a/05/main.c b/05/main.c
index b5c3e12..c9ac82e 100644
--- a/05/main.c
+++ b/05/main.c
@@ -1,19 +1,17 @@
long factorial(long x) {
- return x ? x * factorial(x - 1)
+ return x > 0 ? x * factorial(x - 1)
: 1;
}
long fibonacci(long x) {
- return x ?
- x-1 ?
+ return x > 0 ?
+ x > 1 ?
fibonacci(x-1) + fibonacci(x-2)
: 1
: 0;
}
int main(int argc, char **argv) {
- int x = 104;
- x >>= 3;
- return x;
+ return factorial(6);
}