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| author | Juan J. Martinez <jjm@usebox.net> | 2023-05-23 16:06:46 +0100 |
|---|---|---|
| committer | Juan J. Martinez <jjm@usebox.net> | 2023-05-23 16:08:48 +0100 |
| commit | c5dd4897e4d7f45108b6955bebf2d4b5f22a3652 (patch) | |
| tree | a85d5b933fe2dccf57dd476194a27b0f5d99becd /README.md | |
| parent | 5584f79fff0fdfc8e4430eea3867c729b82f4152 (diff) | |
| download | tr8vm-c5dd4897e4d7f45108b6955bebf2d4b5f22a3652.tar.gz tr8vm-c5dd4897e4d7f45108b6955bebf2d4b5f22a3652.zip | |
Add cmpi, cmpd, ldi and ldd
Diffstat (limited to 'README.md')
| -rw-r--r-- | README.md | 27 |
1 files changed, 26 insertions, 1 deletions
@@ -225,7 +225,8 @@ A label is defined as an ID that ends in `:`. All the instructions are 16-bit, with the exception of `JMP addr` and `CALL addr` that use an extra 16-bit parameter for "addr". All the instructions take -the same time to run, and being 4 MIPS it can fit `66666` instructions in a +the same time to run (with the exception of `cmpi`, `cmpd`, `ldi` and `ldd` +that take extra time), and being 4 MIPS it can fit `66666` instructions in a frame (at 60Hz). There are no 16-bit registers, but they can be implemented with 2 registers, @@ -336,6 +337,16 @@ Load r1 into the stack on top address plus the immediate value. **LD r1, [SP + imm]** Load into r1 the stack value on top address plus the immediate value. +**LDI** +Perform a LD of [a : x] to [b : y], and increments x (and a if x overflows) and +y (and b if x overflows). This instruction takes 4 times longer than a regular +instruction. + +**LDD** +Perform a LD of [a : x] to [b : y], and decrements x (and a if x overflows) +and y (and b if x overflows). This instruction takes 4 times longer than a regular +instruction. + #### Stack **PUSH r1** @@ -415,6 +426,20 @@ Perform a SUB of r1 minus the immediate value without storing the result and only updating the flags. Affected flags: ZF, CF, OF, SF +**CMPI** +Perform a SUB of [a : x] minus [b : y], without storing the result and only +updating the flags. It also increments x (and a if x overflows) and y (and b if x +overflows). The flags are not affected by incrementing a, b, x and y. This +instruction takes 4 times longer than a regular instruction. +Affected flags: ZF, CF, OF, SF + +**CMPD** +Perform a SUB of [a : x] minus [b : y], without storing the result and only +updating the flags. It also decrements x (and a if x overflows) and y (and b if +x overflows). The flags are not affected by decrementing a, b, x and y. This +instruction takes 4 times longer than a regular instruction. +Affected flags: ZF, CF, OF, SF + #### Bit Operations **SHL r1, n** |