diff options
| author | oharboe <oharboe> | 2008-05-05 08:07:29 +0000 |
|---|---|---|
| committer | oharboe <oharboe> | 2008-05-05 08:07:29 +0000 |
| commit | c82fe03eaaf5216776c55dd43e01191cd558eb92 (patch) | |
| tree | b3f01656aff6b619c00a0c9a662e9d8e60aad541 | |
| parent | b93ac48f3c323a11a97a39338897c521780a16b9 (diff) | |
| download | zpu-c82fe03eaaf5216776c55dd43e01191cd558eb92.zip zpu-c82fe03eaaf5216776c55dd43e01191cd558eb92.tar.gz | |
added a bit about interrupts
| -rw-r--r-- | zpu/docs/zpu_arch.html | 37 |
1 files changed, 35 insertions, 2 deletions
diff --git a/zpu/docs/zpu_arch.html b/zpu/docs/zpu_arch.html index a1f61a1..8582afb 100644 --- a/zpu/docs/zpu_arch.html +++ b/zpu/docs/zpu_arch.html @@ -1,5 +1,14 @@ <html> <body> +<h1>Index</h1> +<ul> +<li> <a href="#introduction">Introduction</a> +<li> <a href="#instructionset">Instruction set</a> +<li> <a href="#vectors">Jump vectors</a> +<li> <a href="#memorymap">Memory map</a> +<li> <a href="#interrupts">Interrupts</a> +</ul> +<a name="introduction"/> <h1>Introduction</h1> The ZPU is a zero operand, or stack based CPU. The opcodes have a fixed width of 8 bits. <p> @@ -47,6 +56,7 @@ foo: </code> </div> +<a name="instructionset"/> <h1>Instruction set</h1> Only the base instructions are implemented in the architecture. More advanced instructions, like ASHIFTLEFT are emulated in the illegal instruction vector. @@ -364,6 +374,7 @@ end if </tr> </table> +<a name="vectors"/> <h1>Vectors</h1> <table border="1"> <tr><td>Address</td><td>Name</td><td>Description</td></tr> @@ -392,6 +403,7 @@ end if </tr> </table> +<a name="memorymap"/> <h1>Phi memory map</h1> The ZPU architecture does not define a memory map as such, but the GCC + libgloss + ecos hal library uses the memory map below. @@ -767,7 +779,28 @@ memory map below. </TD> </TR> </TABLE> - - +<a name="interrupts"/> +<h1>Interrupts</h1> +The ZPU supports interrupts. +<p> +To trigger an interrupt, the interrupt signal must be asserted. The ZPU does +not define any interrupt disabling mechanism, this must be implemented by the +interrupt controller and controlled via memory mapped IO. +<p> +Interrupts are masked when the IDIM flag is set, i.e. +with consequtive IM instructions. +<p> +The ZPU has an edge triggered interrupt. As the ZPU notices that the interrupt +is asserted, it will execute the interrupt instruction. The interrupt signal +must stay asserted until the ZPU acknowledges it. +<p> +When the interrupt instruction is executed, the PC will be pushed onto the +stack and the PC will be set to the interrupt vector address (0x20). +<p> +Note that the GCC compiler requires three registers r0,r1,r2,r3 for some +rather uncommon operations. These 32 registers are mapped to memory locations 0x0, +0x4, 0x8, 0xc. The default interrupt vector at address 0x20 will load the +value of these memory locations onto the stack, call _zpu_interrupt and +restore them. </body> <html>
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