diff options
author | sanine-a <sanine.not@pm.me> | 2023-05-23 12:33:39 -0500 |
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committer | sanine-a <sanine.not@pm.me> | 2023-05-23 12:33:39 -0500 |
commit | 4d5377870ee554036ac9aab570ac2bc809fc88bd (patch) | |
tree | f6c15b854daeab756caa3e247926e884dfdeff86 /src/vm | |
parent | 86793f0afd74092be507325a40d85bc62bd47597 (diff) |
implement DJN
Diffstat (limited to 'src/vm')
-rw-r--r-- | src/vm/instruction.js | 20 | ||||
-rw-r--r-- | src/vm/instruction.test.js | 40 |
2 files changed, 60 insertions, 0 deletions
diff --git a/src/vm/instruction.js b/src/vm/instruction.js index f323f84..c235b9a 100644 --- a/src/vm/instruction.js +++ b/src/vm/instruction.js @@ -142,3 +142,23 @@ exports.JMN = function(core, pc, ins) { return [core.normalize(pc, 1)]; } } + + +exports.DJN = function(core, pc, ins) { + let test; + + if (ins.b.mode === AddrMode.Immediate) { + ins.b.value -= 1; + test = (ins.b.value !== 0); + } else { + const src = core.getValue(pc, ins.b); + src.b.value -= 1; + test = (src.b.value !== 0); + } + + if (test) { + return [core.getLocation(pc, ins.a)]; + } else { + return [core.normalize(pc, 1)]; + } +} diff --git a/src/vm/instruction.test.js b/src/vm/instruction.test.js index 2880da7..82d9819 100644 --- a/src/vm/instruction.test.js +++ b/src/vm/instruction.test.js @@ -466,3 +466,43 @@ test('JMN correctly jumps in immediate mode', () => { expect(JMN(core, pc, ins)).toEqual([CORESIZE-1]); }); + +test('DJN correctly jumps in non-immediate mode', () => { + const core = new Core(CORESIZE); + const pc = 2; + core.data[pc] = { + opcode: 'DJN', + a: { mode: 'direct', value: -3 }, + b: { mode: 'direct', value: 1 }, + }; + core.data[pc+1] = { + opcode: 'DJN', + a: { mode: 'direct', value: -3 }, + b: { mode: 'direct', value: 1 }, + }; + const ins = core.data[pc]; + + expect(DJN(core, pc, ins)).toEqual([pc+1]); + expect(core.data[pc+1].b.value).toBe(0); + expect(DJN(core, pc, ins)).toEqual([CORESIZE-1]); + expect(core.data[pc+1].b.value).toBe(-1); +}); + + +test('DJN correctly jumps in immediate mode', () => { + const core = new Core(CORESIZE); + const pc = 2; + core.data[pc] = { + opcode: 'DJN', + a: { mode: 'direct', value: -3 }, + b: { mode: 'immediate', value: 1 }, + }; + const ins = core.data[pc]; + + expect(DJN(core, pc, ins)).toEqual([pc+1]); + expect(core.data[pc].b.value).toBe(0); + expect(DJN(core, pc, ins)).toEqual([CORESIZE-1]); + expect(core.data[pc].b.value).toBe(-1); +}); + + |