diff options
| -rw-r--r-- | input/input_bin.c | 139 | ||||
| -rw-r--r-- | test/full-pipeline/006-2-inst-2-words.asm | 2 | ||||
| -rw-r--r-- | test/full-pipeline/007-3-inst-3-words.asm | 3 | ||||
| -rw-r--r-- | test/full-pipeline/008-3-inst-5-words.asm | 3 | ||||
| -rw-r--r-- | test/full-pipeline/009-3-inst-5-words-rev.asm | 3 |
5 files changed, 95 insertions, 55 deletions
diff --git a/input/input_bin.c b/input/input_bin.c index e1c9d0d..8f4c827 100644 --- a/input/input_bin.c +++ b/input/input_bin.c @@ -83,82 +83,111 @@ static int add_instruction(struct instruction inst) return 0; } +size_t disasm_single(struct instruction *i, uint16_t pc, uint16_t inst, uint16_t extra) +{ + int ret = 0; + int extra_used = 0; + void (*disasm_inst)(uint16_t, uint16_t, struct instruction*); + + switch (GET_INST_TYPE(inst)) { + case INST_TYPE_RTYPE: disasm_inst = disasm_rtype; break; + case INST_TYPE_NITYPE: disasm_inst = disasm_nitype; break; + case INST_TYPE_WITYPE: + disasm_inst = disasm_witype; + extra_used = 1; + break; + case INST_TYPE_JTYPE: + /* J Type can be split into three further subtypes: + * - branch (always immediate, 2 bytes) + * - jump reg (2 bytes) + * - jump immediate (4 bytes) + */ + if (inst & MASK_IS_BRANCH) { + disasm_inst = disasm_bimm; + /* hack PC into handler. It's expecting it */ + extra = pc; + } else { + if (inst & MASK_JR) { + disasm_inst = disasm_jreg; + } else { + disasm_inst = disasm_jimm; + extra_used = 1; + } + } + break; + default: + ret = -EINVAL; + break; + } + if (!ret) { + disasm_inst(inst, extra, i); + /* positive return code is bytes consumed */ + ret = extra_used ? 4 : 2; + } + + return ret; +} + static int disasm_file(FILE *f) { int ret = 0; size_t offs = 0; uint16_t inst = 0; - uint8_t c[2] = { 0 }; - size_t extra_read = 0; - uint16_t extra_arg = 0; + uint16_t extra = 0; + uint8_t c[4] = { 0 }; + size_t to_read = 0; + size_t nread = 0; struct instruction i = { 0 }; - void (*disasm_inst)(uint16_t, uint16_t, struct instruction*); - while (!feof(f) && fread(c, sizeof(c), 1, f) == 1) { - extra_read = 0; - inst = c[0] << 8 | c[1]; - switch (GET_INST_TYPE(inst)) { - case INST_TYPE_RTYPE: - disasm_inst = disasm_rtype; - break; - case INST_TYPE_NITYPE: - disasm_inst = disasm_nitype; - break; - case INST_TYPE_WITYPE: - if (fread(c, sizeof(c), 1, f) != 1) { - ret = -errno; - break; - } - extra_read = sizeof(c); - extra_arg = c[0] << 16 | c[1]; - disasm_inst = disasm_witype; - break; - case INST_TYPE_JTYPE: - /* J Type can be split into three further subtypes: - * - branch (always immediate, 2 bytes) - * - jump reg (2 bytes) - * - jump immediate (4 bytes) - */ - if (inst & MASK_IS_BRANCH) { - disasm_inst = disasm_bimm; - extra_arg = offs; + /* prime the pump with two words read */ + to_read = 4; + do { + nread = fread(c, 1, to_read, f); + switch (nread) { + case 0: + if (to_read == 2) { + /* use up what's left in extra */ } else { - if (inst & MASK_JR) { - disasm_inst = disasm_jreg; - } else { - if (fread(c, sizeof(c), 1, f) != 1) { - ret = -errno; - break; - } - extra_arg = c[0] << 16 | c[1]; - extra_read = sizeof(c); - disasm_inst = disasm_jimm; - } + /* just used up 4 bytes, and couldn't read more. break out*/ + goto read_eof; } + case 2: + /* have just read 2 bytes: shift down and pack new in */ + inst = extra; + extra = c[0] << 8 | c[1]; break; - default: - printf("Unhandled instruction at byte %zd\n", offs); - ret = -1; + case 4: + /* have just read 4 bytes: fresh inst and extra needed */ + inst = c[0] << 8 | c[1]; + extra = c[2] << 8 | c[3]; break; + default: + fprintf(stderr, "Internal error: unexpected nread '%zd'\n", nread); + return 1; } - /* Fall out of loop if picking a handler errored */ - if (ret) { - break; - } - disasm_inst(inst, extra_arg, &i); - if (ret < 0) { + ret = disasm_single(&i, offs, inst, extra); + if (ret <= 0) { fprintf(stderr, "Error handling instruction at byte %zd\n", offs); break; } + if (add_instruction(i)) return 1; - offs += sizeof(c) + extra_read; - } + + /* return value from disasm_single is # bytes decoded. Current byte + * offset is adjusted by this, and we need to read this many more bytes + * next time around */ + offs += ret; + to_read = ret; + } while (!feof(f)); +read_eof: + + if (!feof(f)) { perror("fread"); ret = -errno; } - return ret; + return 0; } int input_bin(FILE *f, struct instruction **i, size_t *i_count) diff --git a/test/full-pipeline/006-2-inst-2-words.asm b/test/full-pipeline/006-2-inst-2-words.asm new file mode 100644 index 0000000..c4e2dbc --- /dev/null +++ b/test/full-pipeline/006-2-inst-2-words.asm @@ -0,0 +1,2 @@ +nop +nop diff --git a/test/full-pipeline/007-3-inst-3-words.asm b/test/full-pipeline/007-3-inst-3-words.asm new file mode 100644 index 0000000..717a122 --- /dev/null +++ b/test/full-pipeline/007-3-inst-3-words.asm @@ -0,0 +1,3 @@ +nop +nop +nop diff --git a/test/full-pipeline/008-3-inst-5-words.asm b/test/full-pipeline/008-3-inst-5-words.asm new file mode 100644 index 0000000..c0a33b5 --- /dev/null +++ b/test/full-pipeline/008-3-inst-5-words.asm @@ -0,0 +1,3 @@ +jmp 0 +jmp 0 +nop diff --git a/test/full-pipeline/009-3-inst-5-words-rev.asm b/test/full-pipeline/009-3-inst-5-words-rev.asm new file mode 100644 index 0000000..5592edd --- /dev/null +++ b/test/full-pipeline/009-3-inst-5-words-rev.asm @@ -0,0 +1,3 @@ +nop +jmp 0 +jmp 0 |