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| author | Jan Tuomi <jans.tuomi@gmail.com> | 2023-04-09 19:50:43 +0300 |
|---|---|---|
| committer | Jan Tuomi <jans.tuomi@gmail.com> | 2023-04-09 19:50:43 +0300 |
| commit | a58375eee5d607fbb44620752195eafb9407685e (patch) | |
| tree | 975650c219cfa49dad2c227adf577f7bf1fbb2f5 /src | |
| parent | cdbb38ddd23c9f14efefd2ae11b04dbe965b3540 (diff) | |
Fix relative addressing off-by-one bug
Diffstat (limited to 'src')
| -rwxr-xr-x | src/assembler.py | 4 | ||||
| -rw-r--r-- | src/test.atk16 | 6 |
2 files changed, 4 insertions, 6 deletions
diff --git a/src/assembler.py b/src/assembler.py index 7deb0f0..7420a04 100755 --- a/src/assembler.py +++ b/src/assembler.py @@ -174,7 +174,7 @@ def make_jpr(addr_reg: str) -> list[int]: def make_jpi(address: int, imm: str) -> list[int]: """JPI 0110 XXXI IIII IIII""" imm_e = eval_expr(imm) - imm_e -= address + imm_e = imm_e - address - 1 word = (0b0110 << 12) + \ imm_e return [word] @@ -192,7 +192,7 @@ def make_bri(address: int, flag_s: str, imm: str) -> list[int]: """BRI 1000 XFFI IIII IIII""" flag_s_e = eval_expr(flag_s) imm_e = eval_expr(imm) - imm_e -= address + imm_e = imm_e - address - 1 word = (0b1000 << 12) + \ (flag_s_e << 9) + \ imm_e diff --git a/src/test.atk16 b/src/test.atk16 index da7c7c8..1a7c773 100644 --- a/src/test.atk16 +++ b/src/test.atk16 @@ -2,8 +2,7 @@ ; ROM (and program execution) starts at offset 0x0 @address 0x0 - ldi RA program - jpr RA + jpi program @label ram_offset 0x8000 ; store ram offset for later memory access @@ -20,9 +19,8 @@ ; Check that 10 + 20 = 30 mov RC RA ; RA := result of sum ldi RB 30 ; RB := 30 - ldi RD success sub RA RB RC ; RC := RA - RB - br f_zero RD ; if result is zero, jump to success + bri f_zero success ; if result is zero, jump to success ldi RA 2 ; RA := 2 to signal failure hlt |