commit d956d9b4e938adff3a959c4ab2d45cfdd323c7d6
parent bdc3445101fd47655e34d3c3f4837353f026422a
Author: Nihal Jere <nihal@nihaljere.xyz>
Date: Tue, 16 Nov 2021 19:29:09 -0600
codegen for simple add expressions
Diffstat:
| M | main.c | | | 46 | +++++++++++++++++++++++++++++++++++++++++----- |
| M | prog.nc | | | 2 | +- |
2 files changed, 42 insertions(+), 6 deletions(-)
diff --git a/main.c b/main.c
@@ -421,6 +421,24 @@ enum mod {
};
size_t
+add_r_imm(char *buf, enum Register reg, uint64_t imm)
+{
+ uint8_t mov[] = {0x48, 0x81};
+ uint8_t op1 = (MOD_DIRECT << 6) | reg;
+ if (buf) {
+ memcpy(buf, mov, 2);
+ buf += 2;
+ *(buf++) = op1;
+ *(buf++) = imm & 0xFF;
+ *(buf++) = (imm >> 8) & 0xFF;
+ *(buf++) = (imm >> 16) & 0xFF;
+ *(buf++) = (imm >> 24) & 0xFF;
+ }
+
+ return 7;
+}
+
+size_t
mov_r_imm(char *buf, enum Register reg, uint64_t imm)
{
uint8_t mov[] = {0x48, 0xc7};
@@ -447,11 +465,29 @@ genexpr(char *buf, size_t idx, int reg)
size_t len = 0;
char *ptr = buf;
struct expr *expr = &exprs.data[idx];
- if (expr->kind == EXPR_LIT && expr->d.v.type == P_INT) {
- len = mov_r_imm(ptr ? ptr + len : ptr, reg, expr->d.v.v.val);
- } else if (expr->kind == EXPR_LIT && expr->d.v.type == P_STR) {
- int addr = data_push(expr->d.v.v.s.ptr, expr->d.v.v.s.len);
- len = mov_r_imm(ptr ? ptr + len : ptr, reg, addr);
+ if (expr->kind == EXPR_LIT) {
+ switch (expr->d.v.type) {
+ case P_INT:
+ len = mov_r_imm(ptr ? ptr + len : ptr, reg, expr->d.v.v.val);
+ break;
+ case P_STR:
+ int addr = data_push(expr->d.v.v.s.ptr, expr->d.v.v.s.len);
+ len = mov_r_imm(ptr ? ptr + len : ptr, reg, addr);
+ break;
+ default:
+ error("genexpr: unknown value type!");
+ }
+ } else if (expr->kind == EXPR_BINARY) {
+ switch (expr->d.op) {
+ case OP_PLUS:
+ struct expr *left = &exprs.data[expr->left];
+ struct expr *right = &exprs.data[expr->right];
+ len = mov_r_imm(ptr ? ptr + len : ptr, reg, left->d.v.v.val);
+ len += add_r_imm(ptr ? ptr + len : ptr, reg, right->d.v.v.val);
+ break;
+ default:
+ error("genexpr: unknown binary op!");
+ }
} else {
error("genexpr: could not generate code for expression");
}
diff --git a/prog.nc b/prog.nc
@@ -1,3 +1,3 @@
-syscall(1, 0, "hello", 5)
+syscall(+ 1 0, 0, "hello", 5)
syscall(1, 0, " world", 6)
syscall(60, 0)
