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65816.js
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handle the carry bit properly when in decimal mode for adc

This commit is contained in:
Preston Skupinski 2011-09-03 22:07:44 -04:00
parent 7cee0a3cd1
commit b505f7a50d
2 changed files with 40 additions and 2 deletions
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8
cpu.js
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@ -3620,11 +3620,13 @@ var ADC_const = {
ones = bytes[0] & 0x0f;
tens = bytes[0] >>4;
var dec_arg = (tens*10)+ones;
var result = dec_a + dec_arg;
var result = dec_a + dec_arg + cpu.p.c;
// Check for decimal overflow.
if(result>99) {
result -= 99;
cpu.p.c = 1;
} else {
cpu.p.c = 0;
}
var digits = result.toString(10).split("");
var i = 0;
@ -3667,11 +3669,13 @@ var ADC_const = {
hundreds = (argument >> 8) & 0xf;
thousands = (argument >> 12) & 0xf;
var dec_arg = (thousands*1000)+(hundreds*100)+(tens*10)+ones;
var result = dec_a + dec_arg;
var result = dec_a + dec_arg + cpu.p.c;
// Check for decimal overflow.
if(result>9999) {
result -= 9999;
cpu.p.c = 1;
} else {
cpu.p.c = 0;
}
var digits = result.toString(10).split("");
var i = 0;

34
test/tests.js
View File

@ -648,6 +648,23 @@ function test_adc() {
equals(cpu.p.e, 0, "The hidden e flag of the p status register should "+
"be 0 for native mode.");
});
test("Test that ADC handles decimal mode with legal BCD numbers in 8-bit "+
"memory/accumulator mode with double digit numbers with the carry "+
"bit set", function() {
var cpu = new CPU_65816();
cpu.execute("18fb38f8a9156926");
equals(cpu.r.a, 0x42, "0x15 + 0x26 should result in 0x42 with decimal "+
"mode on and with 8-bit memory/accumulator mode "+
"and the carry bit set.");
equals(cpu.p.c, 0, "The carry flag of the p status register should be "+
"clear after no decimal overflow.");
equals(cpu.p.d, 1, "Decimal mode should be set to 1 in the p status "+
"register.");
equals(cpu.p.m, 1, "The m flag of the p status register should be 1 for "+
"8-bit memory/accumulator mode.");
equals(cpu.p.e, 0, "The hidden e flag of the p status register should "+
"be 0 for native mode.");
});
test("Test that ADC handles decimal mode with legal BCD numbers in 8-bit "+
"memory/accumulator mode when adding two numbers that cause an "+
"overflow.", function() {
@ -715,6 +732,23 @@ function test_adc() {
equals(cpu.p.e, 0, "The hidden e flag of the p status register should "+
"be 0 for native mode.");
});
test("Test that ADC handles decimal mode with legal BCD numbers in 16-bit "+
"memory/accumulator mode when adding two four digit numbers with the "+
"carry bit set.", function() {
var cpu = new CPU_65816();
cpu.execute("18fb38f8c220a90110699939");
equals(cpu.r.a, 0x5001, "0x1001 + 0x3999 should result in 0x5001 with "+
"decimal mode on and with 16-bit "+
"memory/accumulator mode and the carry flag set.");
equals(cpu.p.c, 0, "The carry flag of the p status register should be "+
"clear after no decimal overflow.");
equals(cpu.p.d, 1, "Decimal mode should be set to 1 in the p status "+
"register.");
equals(cpu.p.m, 0, "The m flag of the p status register should be 0 for "+
"16-bit memory/accumulator mode.");
equals(cpu.p.e, 0, "The hidden e flag of the p status register should "+
"be 0 for native mode.");
});
}
function test_branching() {